LED tube lamp

ABSTRACT

An LED tube lamp includes a lamp tube, a heat shrink sleeve covering on an outer surface of the lamp tube, an LED light strip fixed by an adhesive sheet to an inner circumferential surface of the lamp tube, a plurality of LED light sources on the LED light strip, two end caps respectively coupled to two opposite ends of the lamp tube, and a power supply circuit on the light strip. The LED light strip with the plurality of LED light sources and power supply circuit are in the lamp tube.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part application of U.S.application Ser. No. 15/298,955 filed on Oct. 20, 2016, U.S. applicationSer. No. 15/055,630 filed on Feb. 28, 2016, U.S. application Ser. No.15/339,221 filed on Oct. 31, 2016, U.S. application Ser. No. 15/258,068filed on Sep. 7, 2016, U.S. application Ser. No. 15/211,783 filed onJul. 15, 2016, and U.S. application Ser. No. 15/483,368 filed on Apr.10, 2017, wherein the Ser. No. 15/298,955 application is a continuationapplication of U.S. application Ser. No. 14/865,387 filed in UnitedStates on Sep. 25, 2015, which itself claims Chinese priorities under 35U.S.C. § 119(a) of Patent Applications No. CN 201410507660.9 filed onSep. 28, 2014; CN 201410508899.8 filed on Sep. 28, 2014; CN201410623355.6 filed on Nov. 6, 2014; CN 201410734425.5 filed on Dec. 5,2014; CN 201510075925.7 filed on Feb. 12, 2015; CN 201510104823.3 filedon Mar. 11, 2015; CN 201510134586.5 filed on Mar. 26, 2015; CN201510133689.x filed on Mar. 25, 2015; CN 201510136796.8 filed on Mar.27, 2015; CN 201510173861.4 filed on Mar. 14, 2015; CN 201510155807.7filed on Apr. 3, 2015; CN 201510193980.6 filed on Apr. 22, 2015; CN201510372375.5 filed on Jun. 26, 2015; CN 201510259151.3 filed on May19, 2015; CN 201510268927.8 filed on May 22, 2015; CN 201510284720.xfiled on May 29, 2015; CN 201510338027.6 filed on Jun. 17, 2015; CN201510315636.x filed on Jun. 10, 2015; CN 201510373492.3 filed on Jun.26, 2015; CN 201510364735.7 filed on Jun. 26, 2015; CN 201510378322.4filed on Jun. 29, 2015; CN 201510391910.1 filed on Jul. 2, 2015; CN201510406595.5 filed on Jul. 10, 2015; CN 201510482944.1 filed on Aug.7, 2015; CN 201510486115.0 filed on Aug. 8, 2015; CN 201510428680.1filed on Jul. 20, 2015; CN 201510483475.5 filed on Aug. 8, 2015; CN201510555543.4 filed on Sep. 2, 2015; CN 201510557717.0 filed on Sep. 6,2015; CN 201510595173.7 filed on Sep. 18, 2015; CN 201510724263.1 filedon Oct. 29, 2015; and CN 201510726365.7 filed on Oct. 30, 2015, thedisclosures of which are incorporated herein in their entirety byreference.

FIELD OF THE INVENTION

The present disclosure relates to illumination devices, and moreparticularly to an LED tube lamp and its components including the lightsources, electronic components, and end caps.

BACKGROUND

LED lighting technology is rapidly developing to replace traditionalincandescent and fluorescent lightings. LED tube lamps are mercury-freein comparison with fluorescent tube lamps that need to be filled withinert gas and mercury. Thus, it is not surprising that LED tube lampsare becoming a highly desired illumination option among differentavailable lighting systems used in homes and workplaces, which used tobe dominated by traditional lighting options such as compact fluorescentlight bulbs (CFLs) and fluorescent tube lamps. Benefits of LED tubelamps include improved durability and longevity and far less energyconsumption; therefore, when taking into account all factors, they wouldtypically be considered as a cost effective lighting option.

Typical LED tube lamps have a lamp tube, a circuit board disposed insidethe lamp tube with light sources being mounted on the circuit board, andend caps accompanying a power supply provided at two ends of the lamptube with the electricity from the power supply transmitting to thelight sources through the circuit board. However, existing LED tubelamps have certain drawbacks.

Grainy visual appearances are also often found in the aforementionedconventional LED tube lamp. The LED chips spatially arranged on thecircuit board inside the lamp tube are considered as spot light sources,and the lights emitted from these LED chips generally do not contributeuniform illuminance for the LED tube lamp without proper opticalmanipulation. As a result, the entire tube lamp would exhibit a grainyor non-uniform illumination effect to a viewer of the LED tube lamp,thereby negatively affecting the visual comfort and even narrowing theviewing angles of the lights. As a result, the quality and aestheticsrequirements of average consumers would not be satisfied. To addressthis issue, the Chinese patent application with application no. CN201320748271.6 discloses a diffusion tube is disposed inside a glasslamp tube to avoid grainy visual effects.

However, the disposition of the diffusion tube incurs an interface onthe light transmission path to increase the likelihood of totalreflection and therefore decrease the light outputting efficiency. Inaddition, the optical rotatory absorption of the diffusion tubedecreases the light outputting efficiency.

Furthermore, all of the electronic components of the power supplycircuit disclosed in the Chinese patent application with application no.CN 201320748271.6 are in the end caps. The heat dissipation of the powersupply circuit in the small space of the end cap illustrated in theChinese application is insufficient, therefore the power supply circuitis easier to be damaged.

Next, the driving of an LED uses a DC driving signal. The driving signalfor a fluorescent lamp is a low-frequency and low-voltage AC signal asprovided by an AC powerline, a high-frequency and high-voltage AC signalprovided by a ballast, or even a DC signal provided by a battery foremergency lighting applications. Since the voltages and frequencyspectrums of these types of signals differ significantly, simplyperforming a rectification to produce the required DC driving signal inan LED tube lamp is not competent at achieving the LED tube lamp'scompatibility with traditional driving systems of a fluorescent lamp.

Common main types of ballast include instant-start ballast andprogram-start ballast. A ballast typically includes a resonant circuitand is designed to match the loading characteristics of a fluorescentlamp in driving the fluorescent lamp. However, an LED is a nonlinearcomponent with significantly different characteristics from afluorescent lamp. Therefore, using an LED tube lamp with an electricalballast impacts the resonant circuit design of the electrical ballast,causing a compatibility problem. Generally, a program-start ballast willdetect the presence of a filament in a fluorescent lamp, but traditionalLED driving circuits cannot support the detection and may cause afailure of the filament detection and thus failure of the starting ofthe LED tube lamp. Further, electrical ballast is in effect a currentsource, and when it acts as a power supply of a DC-to-DC convertercircuit in an LED tube lamp, problems of overvoltage and overcurrent orundervoltage and undercurrent are likely to occur, resulting in damagingof electronic components in the LED tube lamp or unstable provision oflighting by the LED tube lamp.

Accordingly, the prevent disclosure and its embodiments are hereinprovided.

SUMMARY OF THE INVENTION

It's specially noted that the present disclosure may actually includeone or more inventions claimed currently or not yet claimed, and foravoiding confusion due to unnecessarily distinguishing between thosepossible inventions at the stage of preparing the specification, thepossible plurality of inventions herein may be collectively referred toas “the (present) invention” herein.

Various embodiments are summarized in this section, and are describedwith respect to the “present invention,” which terminology is used todescribe certain presently disclosed embodiments, whether claimed ornot, and is not necessarily an exhaustive description of all possibleembodiments, but rather is merely a summary of certain embodiments.Certain of the embodiments described below as various aspects of the“present invention” can be combined in different manners to form an LEDtube lamp or a portion thereof.

The present invention provides a novel LED tube lamp, and aspectsthereof.

According to one embodiment, an LED tube lamp comprises a lamp tube, aheat shrink sleeve covering on an outer surface of the lamp tube, an LEDlight strip in the lamp tube, a plurality of LED light sources on theLED light strip, two end caps respectively coupled to two opposite endsof the lamp tube, and a power supply circuit comprising a plurality ofelectronic components. All of the electronic components of the powersupply circuit are on the light strip.

According to one embodiment, the thickness of the heat shrink sleeve isfrom 20 um to 200 um and the heat shrink sleeve is substantiallytransparent with respect to wavelength of light from the plurality ofLED light sources.

According to one embodiment, the LED tube lamp further comprises areflective film on an inner circumferential surface of the lamp tube.

According to one embodiment, a ratio of a circumferential length of thereflective film along the inner circumferential surface of the lamp tubeto a circumferential length of the lamp tube is about 0.3 to 0.5.

According to one embodiment, the reflective film has an opening foraccommodating the LED light strip.

According to one embodiment, the LED tube lamp further comprises adiffusion film on the inner surface of the lamp tube.

According to one embodiment, the LED light strip is fixed by an adhesivesheet to an inner circumferential surface of the lamp tube.

According to one embodiment, the LED light strip has a widened partoccupying a circumference area of the inner surface of the lamp tube anda ratio of the length of the LED light strip along the circumferentialdirection to the circumferential length of the lamp tube is about 0.3 to0.5.

According to one embodiment, each of the end caps has two pins forreceiving an external driving signal. The plurality of the electroniccomponents of the power supply circuit comprises a rectifying circuit, afiltering circuit, and an LED module. The rectifying circuit isconfigured to rectify the external driving signal to produce a rectifiedsignal. The filtering circuit is connected to the rectifying circuit andconfigured to produce a filtered signal. The LED module has theplurality of LED light sources for emitting light.

According to one embodiment, the plurality of the electronic componentsof the power supply circuit further comprises a filtering unit. Thefiltering unit is connected between one pin of one of the two end capsand the rectifying circuit.

According to one embodiment, the filtering unit comprises an inductor.The rectifying circuit comprises a current-limiting capacitor and arectifying unit connected with the current-limiting capacitor. Thefiltering circuit comprises a capacitor.

According to one embodiment, each of the end caps has two pins forreceiving an external driving signal. The plurality of the electroniccomponents of the power supply circuit comprises four filtering units, afirst current-limiting capacitor, a second current-limiting capacitor,two rectifying circuits, and a capacitor connected in parallel with theLED light sources. Two of the four filtering units are connected inseries between the two pins of one of the two end caps. The other two ofthe four filtering units are connected in series between the two pins ofthe other of the two end caps. One end of the first current-limitingcapacitor is connected to a connection node between the two filteringunits connected in series. One end of the second current-limitingcapacitor is connected to a connection node between the other twofiltering units connected in series. The two rectifying circuits arecoupled to the LED light sources. One of the rectifying circuits isconnected to another end of the first current-limiting capacitor and theother rectifying circuit is connected to another end of the secondcurrent-limiting capacitor.

According to one embodiment, an LED tube lamp comprises a lamp tube, anLED light strip in the lamp tube, a plurality of LED light sources onthe LED light strip, two end caps respectively coupled to two oppositeends of the lamp tube, and a power supply circuit. Each of the end capshas two pins. The power supply circuit has a plurality of electroniccomponents. All of the electronic components of the power supply circuitare on the light strip. Each of the end caps comprises a plurality ofopenings formed thereon, and the plurality of openings of one of the endcaps are symmetric to each other with respect to a plane passing throughthe middle of a line connecting the two pins and perpendicular to theline connecting the two pins.

According to one embodiment, the LED tube lamp further comprises a hotmelt adhesive. The end caps are adhered, respectively, to opposite endsof the lamp tube via the hot melt adhesive.

According to one embodiment, the number of the openings on one of theend caps is two.

According to one embodiment, the number of the plurality of openings onone of the end caps is three, and the three openings are arranged in ashape of an arc.

According to one embodiment, the three openings are arranged in a shapeof an arc with gradually varying lengths.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view schematically illustrating an LED tube lampaccording to one embodiment of the present invention;

FIG. 1A is a perspective view schematically illustrating the differentlength end caps of an LED tube lamp according to another embodiment ofthe present invention to illustrate;

FIG. 1B is an exemplary exploded view schematically illustrating the LEDtube lamp shown in FIG. 1;

FIG. 2 illustrates an exploded view of an LED tube lamp including a heatshrink sleeve according to an embodiment of the present invention;

FIG. 3 is a perspective view schematically illustrating front and top ofan end cap of the LED tube lamp according to one embodiment of thepresent invention;

FIG. 4 is an exemplary perspective view schematically illustratingbottom of the end cap as shown in FIG. 3;

FIG. 5 is a plane cross-sectional partial view schematicallyillustrating a connecting region of the end cap and the lamp tube of theLED tube lamp according to one embodiment of the present invention;

FIG. 6 is a perspective cross-sectional view schematically illustratinginner structure of an all-plastic end cap (having a magnetic metalmember and hot melt adhesive inside) according to another embodiment ofthe present invention;

FIG. 7 is a perspective view schematically illustrating the all-plasticend cap and the lamp tube being bonded together by utilizing aninduction coil according to certain embodiments of the presentinvention;

FIG. 8 is a perspective view schematically illustrating a supportingportion and a protruding portion of the electrically insulating tube ofthe end cap of the LED tube lamp according to the another embodiment ofthe present invention;

FIG. 9 is an exemplary plane cross-sectional view schematicallyillustrating the inner structure of the electrically insulating tube andthe magnetic metal member of the end cap of FIG. 8 taken along a lineX-X;

FIG. 10 is a plane view schematically illustrating the configuration ofthe openings on surface of the magnetic metal member of the end cap ofthe LED tube lamp according to the another embodiment of the presentinvention;

FIG. 11 is a plane view schematically illustrating theindentation/embossment on a surface of the magnetic metal member of theend cap of the LED tube lamp according to certain embodiments of thepresent invention;

FIG. 12 is an exemplary plane cross-sectional view schematicallyillustrating the structure of the connection of the end cap of FIG. 8and the lamp tube along a radial axis of the lamp tube, where theelectrically insulating tube is in shape of a circular ring;

FIG. 13 is an exemplary plane cross-sectional view schematicallyillustrating the structure of the connection of the end cap of FIG. 8and the lamp tube along a radial axis of the lamp tube, where theelectrically insulating tube is in shape of an elliptical or oval ring;

FIG. 14 is a perspective view schematically illustrating still anotherend cap of an LED tube lamp according to still another embodiment of theprevent invention;

FIG. 15 is a plane cross-sectional view schematically illustrating endstructure of a lamp tube of the LED tube lamp according to oneembodiment of the present invention;

FIG. 16 is an exemplary plane cross-sectional view schematicallyillustrating the local structure of the transition region of the end ofthe lamp tube of FIG. 15;

FIG. 17 is a plane cross-sectional view schematically illustratinginside structure of the lamp tube of the LED tube lamp according to oneembodiment of the present invention, wherein two reflective films arerespectively adjacent to two sides of the LED light strip along thecircumferential direction of the lamp tube;

FIG. 18 is a plane cross-sectional view schematically illustratinginside structure of the lamp tube of the LED tube lamp according toanother embodiment of the present invention, wherein only a reflectivefilm is disposed on one side of the LED light strip along thecircumferential direction of the lamp tube;

FIG. 19 is a plane cross-sectional view schematically illustratinginside structure of the lamp tube of the LED tube lamp according tostill another embodiment of the present invention, wherein thereflective film is under the LED light strip and extends at both sidesalong the circumferential direction of the lamp tube;

FIG. 20 is a plane cross-sectional view schematically illustratinginside structure of the lamp tube of the LED tube lamp according to yetanother embodiment of the present invention, wherein the reflective filmis under the LED light strip and extends at only one side along thecircumferential direction of the lamp tube;

FIG. 21 is a plane cross-sectional view schematically illustratinginside structure of the lamp tube of the LED tube lamp according tostill yet another embodiment of the present invention, wherein tworeflective films are respectively adjacent to two sides of the LED lightstrip and extending along the circumferential direction of the lamptube;

FIG. 22 is a plane sectional view schematically illustrating the LEDlight strip is a bendable circuit sheet with ends thereof passing acrossthe transition region of the lamp tube of the LED tube lamp to besoldering bonded to the output terminals of the power supply accordingto one embodiment of the present invention;

FIG. 23 is a plane cross-sectional view schematically illustrating abi-layered structure of the bendable circuit sheet of the LED lightstrip of the LED tube lamp according to an embodiment of the presentinvention;

FIG. 24 is a perspective view schematically illustrating the solderingpad of the bendable circuit sheet of the LED light strip for solderingconnection with the printed circuit board of the power supply of the LEDtube lamp according to one embodiment of the present invention;

FIG. 25 is a plane view schematically illustrating the arrangement ofthe soldering pads of the bendable circuit sheet of the LED light stripof the LED tube lamp according to one embodiment of the presentinvention;

FIG. 26 is a plane view schematically illustrating a row of threesoldering pads of the bendable circuit sheet of the LED light strip ofthe LED tube lamp according to another embodiment of the presentinvention;

FIG. 27 is a plane view schematically illustrating two rows of solderingpads of the bendable circuit sheet of the LED light strip of the LEDtube lamp according to still another embodiment of the presentinvention;

FIG. 28 is a plane view schematically illustrating a row of foursoldering pads of the bendable circuit sheet of the LED light strip ofthe LED tube lamp according to yet another embodiment of the presentinvention;

FIG. 29 is a plane view schematically illustrating two rows of twosoldering pads of the bendable circuit sheet of the LED light strip ofthe LED tube lamp according to yet still another embodiment of thepresent invention;

FIG. 30 is a plane view schematically illustrating through holes areformed on the soldering pads of the bendable circuit sheet of the LEDlight strip of the LED tube lamp according to one embodiment of thepresent invention;

FIG. 31 is a plane cross-sectional view schematically illustratingsoldering bonding process utilizing the soldering pads of the bendablecircuit sheet of the LED light strip of FIG. 30 taken from side view andthe printed circuit board of the power supply according to oneembodiment of the present invention;

FIG. 32 is a plane cross-sectional view schematically illustratingsoldering bonding process utilizing the soldering pads of the bendablecircuit sheet of the LED light strip of FIG. 30 taken from side view andthe printed circuit board of the power supply according to anotherembodiment of the present invention, wherein the through hole of thesoldering pads is near the edge of the bendable circuit sheet;

FIG. 33 is a plane view schematically illustrating notches formed on thesoldering pads of the bendable circuit sheet of the LED light strip ofthe LED tube lamp according to one embodiment of the present invention;

FIG. 34 is an exemplary plane cross-sectional view of FIG. 33 takenalong a line A-A′;

FIG. 35 is a perspective view schematically illustrating a circuit boardassembly composed of the bendable circuit sheet of the LED light stripand the printed circuit board of the power supply according to anotherembodiment of the present invention;

FIG. 36 is a perspective view schematically illustrating anotherarrangement of the circuit board assembly of FIG. 35;

FIG. 37 is a perspective view schematically illustrating an LED leadframe for the LED light sources of the LED tube lamp according to oneembodiment of the present invention;

FIG. 38 is a perspective view schematically illustrating a power supplyof the LED tube lamp according to one embodiment of the presentinvention;

FIG. 39 is a perspective view schematically illustrating the printedcircuit board of the power supply, which is perpendicularly adhered to ahard circuit board made of aluminum via soldering according to anotherembodiment of the present invention;

FIG. 40 is a perspective view illustrating a thermos-compression headused in soldering the bendable circuit sheet of the LED light strip andthe printed circuit board of the power supply according to oneembodiment of the present invention;

FIG. 41 is a plane view schematically illustrating the thicknessdifference between two solders on the pads of the bendable circuit sheetof the LED light strip or the printed circuit board of the power supplyaccording to one embodiment of the invention;

FIG. 42 is a perspective view schematically illustrating the solderingvehicle for soldering the bendable circuit sheet of the LED light stripand the printed circuit board of the power supply according to oneembodiment of the invention;

FIG. 43 is an exemplary plan view schematically illustrating a rotationstatus of the rotary platform of the soldering vehicle in FIG. 41;

FIG. 44 is a plan view schematically illustrating an external equipmentfor heating the hot melt adhesive according to another embodiment of thepresent invention;

FIG. 45 is a cross-sectional view schematically illustrating the hotmelt adhesive having uniformly distributed high permeability powderparticles with small particle size according to one embodiment of thepresent invention;

FIG. 46 is a cross-sectional view schematically illustrating the hotmelt adhesive having non-uniformly distributed high permeability powderparticles with small particle size according to another embodiment ofthe present invention, wherein the powder particles form a closedelectric loop;

FIG. 47 is a cross-sectional view schematically illustrating the hotmelt adhesive having non-uniformly distributed high permeability powderparticles with large particle size according to yet another embodimentof the present invention, wherein the powder particles form a closedelectric loop;

FIG. 48 is a perspective view schematically illustrating the bendablecircuit sheet of the LED light strip is formed with two conductivewiring layers according to another embodiment of the present invention;

FIG. 49A is a block diagram of an exemplary power supply module 250 inan LED tube lamp according to some embodiments of the present invention;

FIG. 49B is a block diagram of an exemplary power supply module 250 inan LED tube lamp according to some embodiments of the present invention;

FIG. 49C is a block diagram of an exemplary LED lamp according to someembodiments of the present invention;

FIG. 49D is a block diagram of an exemplary power supply module 250 inan LED tube lamp according to some embodiments of the present invention;

FIG. 49E is a block diagram of an LED lamp according to some embodimentsof the present invention;

FIG. 50A is a schematic diagram of a rectifying circuit according tosome embodiments of the present invention;

FIG. 50B is a schematic diagram of a rectifying circuit according tosome embodiments of the present invention;

FIG. 50C is a schematic diagram of a rectifying circuit according tosome embodiments of the present invention;

FIG. 50D is a schematic diagram of a rectifying circuit according tosome embodiments of the present invention;

FIG. 51A is a schematic diagram of a terminal adapter circuit accordingto some embodiments of the present invention;

FIG. 51B is a schematic diagram of a terminal adapter circuit accordingto some embodiments of the present invention;

FIG. 51C is a schematic diagram of a terminal adapter circuit accordingto some embodiments of the present invention;

FIG. 51D is a schematic diagram of a terminal adapter circuit accordingto some embodiments of the present invention;

FIG. 52A is a block diagram of a filtering circuit according to someembodiments of the present invention;

FIG. 52B is a schematic diagram of a filtering unit according to someembodiments of the present invention;

FIG. 52C is a schematic diagram of a filtering unit according to someembodiments of the present invention;

FIG. 52D is a schematic diagram of a filtering unit according to someembodiments of the present invention;

FIG. 52E is a schematic diagram of a filtering unit according to someembodiments of the present invention;

FIG. 53A is a schematic diagram of an LED module according to someembodiments of the present invention;

FIG. 53B is a schematic diagram of an LED module according to someembodiments of the present invention;

FIG. 53C is a plan view of a circuit layout of the LED module accordingto some embodiments of the present invention;

FIG. 53D is a plan view of a circuit layout of the LED module accordingto some embodiments of the present invention;

FIG. 53E is a plan view of a circuit layout of the LED module accordingto some embodiments of the present invention;

FIG. 54A is a block diagram of an exemplary power supply module in anLED lamp according to some embodiments of the present invention;

FIG. 54B is a block diagram of a driving circuit according to someembodiments of the present invention;

FIG. 54C is a schematic diagram of a driving circuit according to someembodiments of the present invention;

FIG. 54D is a schematic diagram of a driving circuit according to someembodiments of the present invention;

FIG. 54E is a schematic diagram of a driving circuit according to someembodiments of the present invention;

FIG. 54F is a schematic diagram of a driving circuit according to someembodiments of the present invention;

FIG. 54G is a block diagram of a driving circuit according to someembodiments of the present invention;

FIG. 54H is a graph illustrating the relationship between the voltageVin and the objective current Iout according to certain embodiments ofthe present invention;

FIG. 55A is a block diagram of an exemplary power supply module in anLED lamp according to some embodiments of the present invention;

FIG. 55B is a schematic diagram of an anti-flickering circuit accordingto some embodiments of the present invention;

FIG. 56A is a block diagram of an exemplary power supply module in anLED lamp according to some embodiments of the present invention;

FIG. 56B is a schematic diagram of a protection circuit according tosome embodiments of the present invention;

FIG. 57A is a block diagram of an exemplary power supply module in anLED lamp according to some embodiments of the present invention;

FIG. 57B is a schematic diagram of a mode switching circuit in an LEDlamp according to some embodiments of the present invention;

FIG. 57C is a schematic diagram of a mode switching circuit in an LEDlamp according to some embodiments of the present invention;

FIG. 57D is a schematic diagram of a mode switching circuit in an LEDlamp according to some embodiments of the present invention;

FIG. 57E is a schematic diagram of a mode switching circuit in an LEDlamp according to some embodiments of the present invention;

FIG. 57F is a schematic diagram of a mode switching circuit in an LEDlamp according to some embodiments of the present invention;

FIG. 57G is a schematic diagram of a mode switching circuit in an LEDlamp according to some embodiments of the present invention;

FIG. 57H is a schematic diagram of a mode switching circuit in an LEDlamp according to some embodiments of the present invention;

FIG. 57I is a schematic diagram of a mode switching circuit in an LEDlamp according to some embodiment of the present invention;

FIG. 58A is a block diagram of an exemplary power supply module in anLED lamp according to some embodiments of the present invention;

FIG. 58B is a block diagram of an exemplary power supply module in anLED lamp according to some embodiments of the present invention;

FIG. 58C illustrates an arrangement with a ballast-compatible circuit inan LED lamp according to some embodiments of the present invention;

FIG. 58D is a block diagram of an exemplary power supply module in anLED lamp according to some embodiments of the present invention;

FIG. 58E is a block diagram of an exemplary power supply module in anLED lamp according to some embodiments of the present invention;

FIG. 58F is a schematic diagram of a ballast-compatible circuitaccording to some embodiments of the present invention;

FIG. 58G is a block diagram of an exemplary power supply module in anLED lamp according to some embodiments of the present invention;

FIG. 58H is a schematic diagram of a ballast-compatible circuitaccording to some embodiments of the present invention;

FIG. 58I illustrates a ballast-compatible circuit according to someembodiments of the present invention;

FIG. 59A is a block diagram of an exemplary power supply module in anLED tube lamp according to some embodiments of the present invention;

FIG. 59B is a block diagram of an exemplary power supply module in anLED tube lamp according to some embodiments of the present invention;

FIG. 59C is a block diagram of an exemplary power supply module in anLED tube lamp according to some embodiments of the present invention;

FIG. 59D is a schematic diagram of a ballast-compatible circuitaccording to some embodiments of the present invention, which isapplicable to the embodiments shown in FIGS. 59A and 59B and thedescribed modification thereof;

FIG. 60A is a block diagram of an exemplary power supply module in anLED tube lamp according to some embodiments of the present invention;

FIG. 60B is a schematic diagram of a filament-simulating circuitaccording to some embodiments of the present invention;

FIG. 60C is a schematic block diagram including a filament-simulatingcircuit according to some embodiments of the present invention;

FIG. 60D is a schematic block diagram including a filament-simulatingcircuit according to some embodiments of the present invention;

FIG. 60E is a schematic diagram of a filament-simulating circuitaccording to some embodiments of the present invention;

FIG. 60F is a schematic block diagram including a filament-simulatingcircuit according to some embodiments of the present invention;

FIG. 61A is a block diagram of an exemplary power supply module in anLED tube lamp according to some embodiments of the present invention;

FIG. 61B is a schematic diagram of an OVP circuit according to anembodiment of the present invention;

FIG. 62A is a block diagram of an exemplary power supply module in anLED tube lamp according to some embodiments of the present invention;

FIG. 62B is a block diagram of an exemplary power supply module in anLED tube lamp according to some embodiments of the present invention;

FIG. 62C is a block diagram of a ballast detection circuit according tosome embodiments of the present invention;

FIG. 62D is a schematic diagram of a ballast detection circuit accordingto some embodiments of the present invention;

FIG. 62E is a schematic diagram of a ballast detection circuit accordingto some embodiments of the present invention;

FIG. 63A is a block diagram of an exemplary power supply module in anLED tube lamp according to some embodiments of the present invention;

FIG. 63B is a block diagram of an exemplary power supply module in anLED tube lamp according to some embodiments of the present invention;

FIG. 63C is a schematic diagram of an auxiliary power module accordingto an embodiment of the present invention;

FIG. 64 is a block diagram of an exemplary power supply module in an LEDtube lamp according to some embodiments of the present invention.

FIG. 65 illustrates a block diagram of an exemplary power supply modulein an LED tube lamp according to one embodiment of the presentinvention.

DETAILED DESCRIPTION

The present disclosure provides a novel LED tube lamp. The presentdisclosure will now be described in the following embodiments withreference to the drawings. The following descriptions of variousembodiments of this invention are presented herein for purpose ofillustration and giving examples only. It is not intended to beexhaustive or to be limited to the precise form disclosed. These exampleembodiments are just that—examples—and many implementations andvariations are possible that do not require the details provided herein.It should also be emphasized that the disclosure provides details ofalternative examples, but such listing of alternatives is notexhaustive. Furthermore, any consistency of detail between variousexamples should not be interpreted as requiring such detail—it isimpracticable to list every possible variation for every featuredescribed herein. The language of the claims should be referenced indetermining the requirements of the invention.

In the drawings, the size and relative sizes of components may beexaggerated for clarity. Like numbers refer to like elements throughout.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the invention. Asused herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. As used herein, the term “and/or” includes any and allcombinations of one or more of the associated listed items and may beabbreviated as “/”.

It will be understood that, although the terms first, second, third etc.may be used herein to describe various elements, components, regions,layers, or steps, these elements, components, regions, layers, and/orsteps should not be limited by these terms. Unless the context indicatesotherwise, these terms are only used to distinguish one element,component, region, layer, or step from another element, component,region, or step, for example as a naming convention. Thus, a firstelement, component, region, layer, or step discussed below in onesection of the specification could be termed a second element,component, region, layer, or step in another section of thespecification or in the claims without departing from the teachings ofthe present invention. In addition, in certain cases, even if a term isnot described using “first,” “second,” etc., in the specification, itmay still be referred to as “first” or “second” in a claim in order todistinguish different claimed elements from each other.

It will be further understood that the terms “comprises” and/or“comprising,” or “includes” and/or “including” when used in thisspecification, specify the presence of stated features, regions,integers, steps, operations, elements, and/or components, but do notpreclude the presence or addition of one or more other features,regions, integers, steps, operations, elements, components, and/orgroups thereof.

It will be understood that when an element is referred to as being“connected” or “coupled” to or “on” another element, it can be directlyconnected or coupled to or on the other element or intervening elementsmay be present. In contrast, when an element is referred to as being“directly connected” or “directly coupled” to another element, there areno intervening elements present. Other words used to describe therelationship between elements should be interpreted in a like fashion(e.g., “between” versus “directly between,” “adjacent” versus “directlyadjacent,” etc.). However, the term “contact,” as used herein refers todirect contact (i.e., touching) unless the context indicates otherwise.

Embodiments described herein will be described referring to plan viewsand/or cross-sectional views by way of ideal schematic views.Accordingly, the exemplary views may be modified depending onmanufacturing technologies and/or tolerances. Therefore, the disclosedembodiments are not limited to those shown in the views, but includemodifications in configuration formed on the basis of manufacturingprocesses. Therefore, regions exemplified in figures may have schematicproperties, and shapes of regions shown in figures may exemplifyspecific shapes of regions of elements to which aspects of the inventionare not limited.

Spatially relative terms, such as “beneath,” “below,” “lower,” “above,”“upper” and the like, may be used herein for ease of description todescribe one element's or feature's relationship to another element(s)or feature(s) as illustrated in the figures. It will be understood thatthe spatially relative terms are intended to encompass differentorientations of the device in use or operation in addition to theorientation depicted in the figures. For example, if the device in thefigures is turned over, elements described as “below” or “beneath” otherelements or features would then be oriented “above” the other elementsor features. Thus, the term “below” can encompass both an orientation ofabove and below. The device may be otherwise oriented (rotated 90degrees or at other orientations) and the spatially relative descriptorsused herein interpreted accordingly.

Terms such as “same,” “equal,” “planar,” or “coplanar,” as used hereinwhen referring to orientation, layout, location, shapes, sizes, amounts,or other measures do not necessarily mean an exactly identicalorientation, layout, location, shape, size, amount, or other measure,but are intended to encompass nearly identical orientation, layout,location, shapes, sizes, amounts, or other measures within acceptablevariations that may occur, for example, due to manufacturing processes.The term “substantially” may be used herein to reflect this meaning.

Terms such as “about” or “approximately” may reflect sizes,orientations, or layouts that vary only in a small relative manner,and/or in a way that does not significantly alter the operation,functionality, or structure of certain elements. For example, a rangefrom “about 0.1 to about 1” may encompass a range such as a 0%-5%deviation around 0.1 and a 0% to 5% deviation around 1, especially ifsuch deviation maintains the same effect as the listed range.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this disclosure belongs. It willbe further understood that terms, such as those defined in commonly useddictionaries, should be interpreted as having a meaning that isconsistent with their meaning in the context of the relevant art and/orthe present application, and will not be interpreted in an idealized oroverly formal sense unless expressly so defined herein.

As used herein, items described as being “electrically connected” areconfigured such that an electrical signal can be passed from one item tothe other. Therefore, a passive electrically conductive component (e.g.,a wire, pad, internal electrical line, etc.) physically connected to apassive electrically insulative component (e.g., a prepreg layer of aprinted circuit board, an electrically insulative adhesive connectingtwo devices, an electrically insulative underfill or mold layer, etc.)is not electrically connected to that component. Moreover, items thatare “directly electrically connected,” to each other are electricallyconnected through one or more passive elements, such as, for example,wires, pads, internal electrical lines, resistors, etc. As such,directly electrically connected components do not include componentselectrically connected through active elements, such as transistors ordiodes.

Components described as thermally connected or in thermal communicationare arranged such that heat will follow a path between the components toallow the heat to transfer from the first component to the secondcomponent. Simply because two components are part of the same device orboard does not make them thermally connected. In general, componentswhich are heat-conductive and directly connected to otherheat-conductive or heat-generating components (or connected to thosecomponents through intermediate heat-conductive components or in suchclose proximity as to permit a substantial transfer of heat) will bedescribed as thermally connected to those components, or in thermalcommunication with those components. On the contrary, two componentswith heat-insulative materials therebetween, which materialssignificantly prevent heat transfer between the two components, or onlyallow for incidental heat transfer, are not described as thermallyconnected or in thermal communication with each other. The terms“heat-conductive” or “thermally-conductive” do not apply to any materialthat provides incidental heat conduction, but are intended to refer tomaterials that are typically known as good heat conductors or known tohave utility for transferring heat, or components having similar heatconducting properties as those materials.

Referring to FIGS. 1, 1A, 1B and 2, an LED tube lamp of one embodimentof the present invention includes a lamp tube 1, an LED light strip 2disposed inside the lamp tube 1, and two end caps 3 respectivelydisposed at two ends of the lamp tube 1. The lamp tube 1 may be made ofplastic or glass. The lengths of the two end caps 3 may be same ordifferent. Referring to FIG. 1A, the length of one end cap may in someembodiments be about 30% to about 80% times the length of the other endcap.

In one embodiment, the lamp tube 1 is made of glass with strengthened ortempered structure to avoid being easily broken and incurring electricalshock occurred to conventional glass made tube lamps, and to avoid thefast aging process that often occurs in plastic made tube lamps. Theglass made lamp tube 1 may be additionally strengthened or tempered by achemical tempering method or a physical tempering method in variousembodiments of the present invention.

An exemplary chemical tempering method is accomplished by exchanging theNa ions or K ions on the glass surface with other alkali metal ions andtherefore changes composition of the glass surface. The sodium (Na) ionsor potassium (K) ions and other alkali metal ions on the glass surfaceare exchanged to form an ion exchange layer on the glass surface. Theglass is then under tension on the inside while under compression on theoutside when cooled to room temperature, so as to achieve the purpose ofincreased strength. The chemical tempering method includes but is notlimited to the following glass tempering methods: high temperature typeion exchange method, the low temperature type ion exchange method,dealkalization, surface crystallization, and/or sodium silicatestrengthening methods, further explained as follows.

An exemplary embodiment of the high temperature type ion exchange methodincludes the following steps: Inserting glass containing sodium oxide(Na₂O) or potassium oxide (K₂O) in the temperature range of thesoftening point and glass transition point into molten salt of lithium,so that the Na ions in the glass are exchanged for Li ions in the moltensalt. Later, the glass is then cooled to room temperature, since thesurface layer containing Li ions has a different expansion coefficientwith respect to the inner layer containing Na ions or K ions, thus thesurface produces residual stress and is reinforced. Meanwhile, the glasscontaining Al₂O₃, TiO₂ and other components, by performing ion exchange,can produce glass crystals having an extremely low coefficient ofexpansion. The crystallized glass surface after cooling produces asignificant amount of pressure, up to 700 MPa, which can enhance thestrength of glass.

An exemplary embodiment of the low-temperature ion exchange methodincludes the following steps: First, a monovalent cation (e.g., K ions)undergoes ion exchange with the alkali ions (e.g. Na ion) on the surfacelayer at a temperature range that is lower than the strain pointtemperature, so as to allow the K ions to penetrate the surface. Forexample, for manufacturing a Na₂O+CaO+SiO₂ system glass, the glass canbe impregnated for ten hours at more than four hundred degrees in themolten salt. The low temperature ion exchange method can easily obtainglass of higher strength, and the processing method is simple, does notdamage the transparent nature of the glass surface, and does not undergoshape distortion.

An exemplary embodiment of dealkalization includes treating glass usingplatinum (Pt) catalyst along with sulfurous acid gas and water in a hightemperature atmosphere. The Na⁺ ions are migrated out and bleed from theglass surface to be reacted with the Pt catalyst, so that the surfacelayer becomes a SiO₂ enriched layer, which results in a low expansionglass and produces compressive stress upon cooling.

The surface crystallization method and the high temperature type ionexchange method are different, but only the surface layer is treated byheat treatment to form low expansion coefficient microcrystals on theglass surface, thus reinforcing the glass.

An exemplary embodiment of the sodium silicate glass strengtheningmethod is a tempering method using sodium silicate (water glass) inwater solution at 100 degrees Celsius and several atmospheres ofpressure treatment, where a stronger/higher strength glass surface thatis harder to scratch is thereby produced.

An exemplary embodiment of the physical tempering method includes but isnot limited to applying a coating to or changing the structure of anobject such as to strengthen the easily broken position. The appliedcoating can be, for example, a ceramic coating, an acrylic coating, or aglass coating depending on the material used. The coating can beperformed in a liquid phase or gaseous phase.

The above glass tempering methods described including physical temperingmethods and chemical tempering methods can be accomplished singly orcombined together in any fashion.

Referring to FIG. 1B and FIG. 15, a glass made lamp tube of an LED tubelamp according to one embodiment of the present invention hasstructure-strengthened end regions described as follows. The glass madelamp tube 1 includes a main body region 102, two rear end regions 101(or just end regions 101) respectively formed at two ends of the mainbody region 102, and end caps 3 that respectively sleeve the rear endregions 101. The outer diameter of at least one of the rear end regions101 is less than the outer diameter of the main body region 102. In theembodiment of FIGS. 1B and 15, the outer diameters of the two rear endregions 101 are less than the outer diameter of the main body region102. In addition, the surface of the rear end region 101 is in parallelwith the surface of the main body region 102 in a cross-sectional view.Specifically, the glass made lamp tube 1 is strengthened at both ends,such that the rear end regions 101 are formed to be strengthenedstructures. In certain embodiments, the rear end regions 101 withstrengthened structure are respectively sleeved with the end caps 3, andthe outer diameters of the end caps 3 and the main body region 102 havelittle or no differences. For example, the end caps 3 may have the sameor substantially the same outer diameters as that of the main bodyregion 102 such that there is no gap between the end caps 3 and the mainbody region 102. In this way, a supporting seat in a packing box fortransportation of the LED tube lamp contacts not only the end caps 3 butalso the lamp tube 1 and makes uniform the loadings on the entire LEDtube lamp to avoid situations where only the end caps 3 are forced,therefore preventing breakage at the connecting portion between the endcaps 3 and the rear end regions 101 due to stress concentration. Thequality and the appearance of the product are therefore improved.

In one embodiment, the end caps 3 and the main body region 102 havesubstantially the same outer diameters. These diameters may have atolerance for example within +/−0.2 millimeter (mm), or in some cases upto +/−1.0 millimeter (mm). Depending on the thickness of the end caps 3,the difference between an outer diameter of the rear end regions 101 andan outer diameter of the main body region 102 can be about 1 mm to about10 mm for typical product applications. In some embodiments, thedifference between the outer diameter of the rear end regions 101 andthe outer diameter of the main body region 102 can be about 2 mm toabout 7 mm.

Referring to FIG. 2, the LED tube lamp 1 may have a heat shrink sleeve190 covering on the outer surface of the lamp tube 1. In someembodiments, the heat shrink sleeve 190 may have a thickness rangingbetween 20 μm and 200 μm and is substantially transparent with respectto the wavelength of light from the LED light sources 202. In someembodiments, the heat shrink sleeve 190 may be made of PFA(perfluoroalkoxy) or PTFE (polytetrafluoroethylene). The heat shrinksleeve 190 may be slightly larger than the lamp tube 1, and may beshrunk and tightly cover the outer surface of the lamp tube 1 whilebeing heated to an appropriate temperature (ex, 260° C. for PFA andPTFE).

Referring to FIG. 15, the lamp tube 1 is further formed with atransition region 103 between the main body region 102 and the rear endregions 101. In one embodiment, the transition region 103 is a curvedregion formed to have cambers at two ends to smoothly connect the mainbody region 102 and the rear end regions 101, respectively. For example,the two ends of the transition region 103 may be arc-shaped in across-section view along the axial direction of the lamp tube 1.Furthermore, one of the cambers connects the main body region 102 whilethe other one of the cambers connects the rear end region 101. In someembodiments, the arc angle of the cambers is greater than 90 degreeswhile the outer surface of the rear end region 101 is a continuoussurface in parallel with the outer surface of the main body region 102when viewed from the cross-section along the axial direction of the lamptube. In other embodiments, the transition region 103 can be withoutcurve or arc in shape. In certain embodiments, the length of thetransition region 103 along the axial direction of the lamp tube 1 isbetween about 1 mm to about 4 mm. Upon experimentation, it was foundthat when the length of the transition region 103 along the axialdirection of the lamp tube 1 is less than 1 mm, the strength of thetransition region would be insufficient; when the length of thetransition region 103 along the axial direction of the lamp tube 1 ismore than 4 mm, the main body region 102 would be shorter and thedesired illumination surface would be reduced, and the end caps 3 wouldbe longer and the more materials for the end caps 3 would be needed.

Referring to FIG. 5 and FIG. 16, in certain embodiments, the lamp tube 1is made of glass, and has a rear end region 101, a main body region 102,and a transition region 103. The transition region 103 has twoarc-shaped cambers at both ends to from an S shape; one camberpositioned near the main body region 102 is convex outwardly, while theother camber positioned near the rear end region 101 is concavedinwardly. Generally speaking, the radius of curvature, R1, of thecamber/arc between the transition region 103 and the main body region102 is smaller than the radius of curvature, R2, of the camber/arcbetween the transition region 103 and the rear end region 101. The ratioR1:R2 may range, for example, from about 1:1.5 to about 1:10, and insome embodiments is more effective from about 1:2.5 to about 1:5, and insome embodiments is even more effective from about 1:3 to about 1:4. Inthis way, the camber/arc of the transition region 103 positioned nearthe rear end region 101 is in compression at outer surfaces and intension at inner surfaces, and the camber/arc of the transition region103 positioned near the main body region 102 is in tension at outersurfaces and in compression at inner surfaces. Therefore, the goal ofstrengthening the transition region 103 of the lamp tube 1 is achieved.

Taking the standard specification for T8 lamp as an example, the outerdiameter of the rear end region 101 is configured between 20.9 mm to 23mm. An outer diameter of the rear end region 101 is less than 20.9 mmwould be too small to fittingly insert the power supply into the lamptube 1. The outer diameter of the main body region 102 is in someembodiments configured to be between about 25 mm to about 28 mm. Anouter diameter of the main body region 102 being less than 25 mm wouldbe inconvenient to strengthen the ends of the main body region 102 asfar as the current manufacturing skills are concerned, while an outerdiameter of the main body region 102 being greater than 28 mm is notcompliant to the industrial standard.

Referring to FIGS. 3 and 4, in one embodiment of the invention, each endcap 3 includes an electrically insulating tube 302, a thermal conductivemember 303 sleeving over the electrically insulating tube 302, and twohollow conductive pins 301 disposed on the electrically insulating tube302. The thermal conductive member 303 can be a metal ring that istubular in shape.

Referring FIG. 5, in one embodiment, one end of the thermal conductivemember 303 extends away from the electrically insulating tube 302 of theend cap 3 and towards one end of the lamp tube 1, and is bonded andadhered to the end of the lamp tube 1 using a hot melt adhesive 6. Inthis way, the end cap 3 by way of the thermal conductive member 303extends to the transition region 103 of the lamp tube 1. In oneembodiment, the thermal conductive member 303 and the transition region103 are closely connected such that the hot melt adhesive 6 would notoverflow out of the end cap 3 and remain on the main body region 102when using the hot melt adhesive 6 to join the thermal conductive member303 and the lamp tube 1. In addition, the electrically insulating tube302 facing toward the lamp tube 1 does not have an end extending to thetransition region 103, and that there is a gap between the electricallyinsulating tube 302 and the transition region 103. In one embodiment,the electrically insulating tube 302 is not limited to being made ofplastic or ceramic, any material that is not a good electrical conductorcan be used.

The hot melt adhesive 6 is a composite including a so-called commonlyknown as “welding mud powder”, and in some embodiments includes one ormore of phenolic resin 2127#, shellac, rosin, calcium carbonate powder,zinc oxide, and ethanol. Rosin is a thickening agent with a feature ofbeing dissolved in ethanol but not dissolved in water. In oneembodiment, a hot melt adhesive 6 having rosin could be expanded tochange its physical status to become solidified when being heated tohigh temperature in addition to the intrinsic viscosity. Therefore, theend cap 3 and the lamp tube 1 can be adhered closely by using the hotmelt adhesive to accomplish automatic manufacture for the LED tubelamps. In one embodiment, the hot melt adhesive 6 may be expansive andflowing and finally solidified after cooling. In this embodiment, thevolume of the hot melt adhesive 6 expands to about 1.3 times theoriginal size when heated from room temperature to about 200 to 250degrees Celsius. The hot melt adhesive 6 is not limited to the materialsrecited herein. Alternatively, a material for the hot melt adhesive 6 tobe solidified immediately when heated to a predetermined temperature canbe used. The hot melt adhesive 6 provided in each embodiments of thepresent invention is durable with respect to high temperature inside theend caps 3 due to the heat resulted from the power supply. Therefore,the lamp tube 1 and the end caps 3 could be secured to each otherwithout decreasing the reliability of the LED tube lamp.

Furthermore, there is formed an accommodation space between the innersurface of the thermal conductive member 303 and the outer surface ofthe lamp tube 1 to accommodate the hot melt adhesive 6, as indicated bythe dotted line B in FIG. 5. For example, the hot melt adhesive 6 can befilled into the accommodation space at a location where a firsthypothetical plane (as indicated by the dotted line B in FIG. 5) beingperpendicular to the axial direction of the lamp tube 1 would passthrough the thermal conductive member, the hot melt adhesive 6, and theouter surface of the lamp tube 1. The hot melt adhesive 6 may have athickness, for example, of about 0.2 mm to about 0.5 mm. In oneembodiment, the hot melt adhesive 6 will be expansive to solidify in andconnect with the lamp tube 1 and the end cap 3 to secure both. Thetransition region 103 brings a height difference between the rear endregion 101 and the main body region 102 to avoid the hot melt adhesives6 being overflowed onto the main body region 102, and thereby savesmanpower to remove the overflowed adhesive and increase the LED tubelamp productivity. The hot melt adhesive 6 is heated by receiving heatfrom the thermal conductive member 303 to which an electricity from anexternal heating equipment is applied, and then expands and finallysolidifies after cooling, such that the end caps 3 are adhered to thelamp tube 1.

Referring to FIG. 5, in one embodiment, the electrically insulating tube302 of the end cap 3 includes a first tubular part 302 a and a secondtubular part 302 b connected along an axial direction of the lamp tube1. The outer diameter of the second tubular part 302 b is less than theouter diameter of the first tubular part 302 a. In some embodiments, theouter diameter difference between the first tubular part 302 a and thesecond tubular part 302 b is between about 0.15 mm and about 0.30 mm.The thermal conductive member 303 sleeves over the outer circumferentialsurface of the second tubular part 302 b. The outer surface of thethermal conductive member 303 is coplanar or substantially flush withrespect to the outer circumferential surface of the first tubular part302 a. For example, the thermal conductive member 303 and the firsttubular part 302 a have substantially uniform exterior diameters fromend to end. As a result, the entire end cap 3 and thus the entire LEDtube lamp may be smooth with respect to the outer appearance and mayhave a substantially uniform tubular outer surface, such that theloading during transportation on the entire LED tube lamp is alsouniform. In one embodiment, a ratio of the length of the thermalconductive member 303 along the axial direction of the end cap 3 to theaxial length of the electrically insulating tube 302 ranges from about1:2.5 to about 1:5.

In one embodiment, for sake of secure adhesion between the end cap 3 andthe lamp tube 1, the second tubular part 302 b is at least partiallydisposed around the lamp tube 1, and the accommodation space furtherincludes a space encompassed by the inner surface of the second tubularpart 302 b and the outer surface of the rear end region 101 of the lamptube 1. The hot melt adhesive 6 is at least partially filled in anoverlapped region (shown by a dotted line “A” in FIG. 5) between theinner surface of the second tubular part 302 b and the outer surface ofthe rear end region 101 of the lamp tube 1. For example, the hot meltadhesive 6 may be filled into the accommodation space at a locationwhere a second hypothetical plane (shown by the dotted line A in FIG. 5)being perpendicular to the axial direction of the lamp tube 1 would passthrough the thermal conductive member 303, the second tubular part 302b, the hot melt adhesive 6, and the rear end region 101.

The hot melt adhesive 6 is not required to completely fill the entireaccommodation space as shown in FIG. 5, especially where a gap isreserved or formed between the thermal conductive member 303 and thesecond tubular part 302 b. For example, in some embodiments, the hotmelt adhesive 6 can be only partially filled into the accommodationspace. During manufacturing of the LED tube lamp, the amount of the hotmelt adhesive 6 coated and applied between the thermal conductive member303 and the rear end region 101 may be appropriately increased, suchthat in the subsequent heating process, the hot melt adhesive 6 can becaused to expand and flow in between the second tubular part 302 b andthe rear end region 101, and thereby solidify after cooling to join thesecond tubular part 302 b and the rear end region 101.

During fabrication of the LED tube lamp, the rear end region 101 of thelamp tube 1 is inserted into one of the end caps 3. In some embodiments,the axial length of the inserted portion of the rear end region 101 ofthe lamp tube 1 accounts for approximately one-third (⅓) to two-thirds(⅔) of the total axial length of the thermal conductive member 303. Onebenefit is that, there will be sufficient creepage distance between thehollow conductive pins 301 and the thermal conductive member 303, andthus it is not easy to form a short circuit leading to dangerouselectric shock to individuals. On the other hand, the creepage distancebetween the hollow conductive pin 301 and the thermal conductive member303 is increased due to the electrically insulating effect of theelectrically insulating tube 302, and thus a high voltage test is morelikely to pass without causing electrical shocks to people.

Furthermore, the presence of the second tubular part 302 b interposedbetween the hot melt adhesive 6 and the thermal conductive member 303may reduce the heat from the thermal conductive member 303 to the hotmelt adhesive 6. To help prevent or minimize this problem, referring toFIG. 4 in one embodiment, the end of the second tubular part 302 bfacing the lamp tube 1 (i.e., away from the first tubular part 302 a) iscircumferentially provided with a plurality of notches 302 c. Thesenotches 302 c help to increase the contact areas between the thermalconductive member 303 and the hot melt adhesive 6 and therefore providerapid heat conduction from the thermal conductive member 303 to the hotmelt adhesive 6 so as to accelerate the solidification of the hot meltadhesive 6. Moreover, the hot melt adhesive 6 electrically insulates thethermal conductive member 303 and the lamp tube 1 so that a user wouldnot be electrically shocked when he touches the thermal conductivemember 303 connected to a broken lamp tube 1.

The thermal conductive member 303 can be made of various heat conductingmaterials. The thermal conductive member 303 can be a metal sheet suchas an aluminum alloy. The thermal conductive member 303 sleeves thesecond tubular part 302 b and can be tubular or ring-shaped. Theelectrically insulating tube 302 may be made of electrically insulatingmaterial, but in some embodiments have low thermal conductivity so as toprevent the heat from reaching the power supply module located insidethe end cap 3 and therefore negatively affecting performance of thepower supply module. In one embodiment, the electrically insulating tube302 is a plastic tube.

Alternatively, the thermal conductive member 303 may be formed by aplurality of metal plates circumferentially arranged on the tubular part302 b with either an equidistant space or a non-equidistant space.

The end cap 3 may be designed to have other kinds of structures orinclude other elements. Referring to FIG. 6, the end cap 3 according toanother embodiment further includes a magnetic metal member 9 within theelectrically insulating tube 302 but excludes the thermal conductivemember 3. The magnetic metal member 9 is fixedly arranged on the innercircumferential surface of the electrically insulating tube 302 andtherefore interposed between the electrically insulating tube 302 andthe lamp tube 1 such that the magnetic metal member 9 is partiallyoverlapped with the lamp tube 1 in the radial direction. In thisembodiment, the whole magnetic metal member 9 is inside the electricallyinsulating tube 302, and the hot melt adhesive 6 is coated on the innersurface of the magnetic metal member 9 (the surface of the magneticmetal tube member 9 facing the lamp tube 1) and adhered to the outerperipheral surface of the lamp tube 1. In some embodiments, the hot meltadhesive 6 covers the entire inner surface of the magnetic metal member9 in order to increase the adhesion area and to improve the stability ofthe adhesion.

Referring to FIG. 7, when manufacturing the LED tube lamp of thisembodiment, the electrically insulating tube 302 is inserted in anexternal heating equipment which is in some embodiments an inductioncoil 11, so that the induction coil 11 and the magnetic metal member 9are disposed opposite (or adjacent) to one another along the radiallyextending direction of the electrically insulating tube 302. Theinduction coil 11 is energized and forms an electromagnetic field, andthe electromagnetic field induces the magnetic metal member 9 to createan electrical current and become heated. The heat from the magneticmetal member 9 is transferred to the hot melt adhesive 6 to make the hotmelt adhesive 6 expansive and flowing and then solidified after cooling,and the bonding for the end cap 3 and the lamp tube 1 can beaccomplished. The induction coil 11 may be made, for example, of redcopper and composed of metal wires having width of, for example, about 5mm to about 6 mm to be a circular coil with a diameter, for example, ofabout 30 mm to about 35 mm, which is a bit greater than the outerdiameter of the end cap 3. Since the end cap 3 and the lamp tube 1 mayhave the same outer diameters, the outer diameter may change dependingon the outer diameter of the lamp tube 1, and therefore the diameter ofthe induction coil 11 used can be changed depending on the type of thelamp tube 1 used. As examples, the outer diameters of the lamp tube forT12, T10, T8, T5, T4, and T2 are 38.1 mm, 31.8 mm, 25.4 mm, 16 mm, 12.7mm, and 6.4 mm, respectively.

Furthermore, the induction coil 11 may be provided with a poweramplifying unit to increase the alternating current power to about 1 to2 times the original. In some embodiments, it is better that theinduction coil 11 and the electrically insulating tube 302 are coaxiallyaligned to make energy transfer more uniform. In some embodiments, adeviation value between the axes of the induction coil 11 and theelectrically insulating tube 302 is not greater than about 0.05 mm. Whenthe bonding process is complete, the end cap 3 and the lamp tube 1 aremoved away from the induction coil. Then, the hot melt adhesive 6absorbs the energy to be expansive and flowing and solidified aftercooling. In one embodiment, the magnetic metal member 9 can be heated toa temperature of about 250 to about 300 degrees Celsius; the hot meltadhesive 6 can be heated to a temperature of about 200 to about 250degrees Celsius. The material of the hot melt adhesive is not limitedhere, and a material of allowing the hot melt adhesive to immediatelysolidify when absorb heat energy can also be used.

In one embodiment, the induction coil 11 may be fixed in position toallow the end cap 3 and the lamp tube 1 to be moved into the inductioncoil 11 such that the hot melt adhesive 6 is heated to expand and flowand then solidify after cooling when the end cap 3 is again moved awayfrom the induction coil 11. Alternatively, the end cap 3 and the lamptube 1 may be fixed in position to allow the induction coil 11 to bemoved to encompass the end cap 3 such that the hot melt adhesive 6 isheated to expand and flow and then solidify after cooling when theinduction coil 11 is again moved away from the end cap 3. In oneembodiment, the external heating equipment for heating the magneticmetal member 9 is provided with a plurality of devices the same as theinduction coils 11, and the external heating equipment moves relative tothe end cap 3 and the lamp tube 1 during the heating process. In thisway, the external heating equipment moves away from the end cap 3 whenthe heating process is completed. However, the length of the lamp tube 1is far greater than the length of the end cap 3 and may be up to above240 cm in some special appliances, and this may cause bad connectionbetween the end cap 3 and the lamp tube 1 during the process that thelamp tube 1 accompany with the end cap 3 to relatively enter or leavethe induction coil 11 in the back and for the direction as mentionedabove when a position error exists.

Referring to FIG. 44, an external heating equipment 110 having aplurality sets of upper and lower semicircular fixtures 11 a is providedto achieve same heating effect as that brought by the induction coils11. In this way, the above-mentioned damage risk due to the relativemovement in back-and-forth direction can be reduced. The upper and lowersemicircular fixtures 11 a each has a semicircular coil made by windinga metal wire of, for example, about 5 mm to about 6 mm wide. Thecombination of the upper and lower semicircular fixtures form a ringwith a diameter, for example, of about 30 mm to about 35 mm, and theinside semicircular coils form a closed loop to become the inductioncoil 11 as mentioned. In this embodiment, the end cap 3 and the lamptube 1 do not relatively move in the back-and-forth manner, but rollinto the notch of the lower semicircular fixture. Specifically, an endcap 3 accompanied with a lamp tube 1 initially roll on a productionline, and then the end cap 3 rolls into the notch of a lowersemicircular fixture, and then the upper and the lower semicircularfixtures are combined to form a closed loop, and the fixtures aredetached when heating is completed. This method reduces the need forhigh position precision and yield problems in production.

Referring to FIG. 6, the electrically insulating tube 302 is furtherdivided into two parts, namely a first tubular part 302 d and a secondtubular part 302 e, i.e. the remaining part. In order to provide bettersupport of the magnetic metal member 9, an inner diameter of the firsttubular part 302 d for supporting the magnetic metal member 9 is largerthan the inner diameter of the second tubular part 302 e which does nothave the magnetic metal member 9, and a stepped structure is formed atthe connection of the first tubular part 302 d and the second tubularpart 302 e. In this way, an end of the magnetic metal member 9 as viewedin an axial direction is abutted against the stepped structure such thatthe entire inner surface of the end cap is smooth and plain.Additionally, the magnetic metal member 9 may be of various shapes,e.g., a sheet-like or tubular-like structure being circumferentiallyarranged or the like, where the magnetic metal member 9 is coaxiallyarranged with the electrically insulating tube 302.

Referring to FIGS. 8 and 9, the electrically insulating tube may befurther formed with a supporting portion 313 on the inner surface of theelectrically insulating tube 302 to be extending inwardly such that themagnetic metal member 9 is axially abutted against the upper edge of thesupporting portion 313. In some embodiments, the thickness of thesupporting portion 313 along the radial direction of the electricallyinsulating tube 302 is between 1 mm to 2 mm. The electrically insulatingtube 302 may be further formed with a protruding portion 310 on theinner surface of the electrically insulating tube 302 to be extendinginwardly such that the magnetic metal member 9 is radially abuttedagainst the side edge of the protruding portion 310 and that the outersurface of the magnetic metal member 9 and the inner surface of theelectrically insulating tube 302 is spaced apart with a gap. Thethickness of the protruding portion 310 along the radial direction ofthe electrically insulating tube 302 is less than the thickness of thesupporting portion 313 along the radial direction of the electricallyinsulating tube 302 and in some embodiments be 0.2 mm to 1 mm in anembodiment.

Referring to FIG. 9, the protruding portion 310 and the supportingportion are connected along the axial direction, and the magnetic metalmember 9 is axially abutted against the upper edge of the supportingportion 313 while radially abutted against the side edge of theprotruding portion 310 such that at least part of the protruding portion310 intervenes between the magnetic metal member 9 and the electricallyinsulating tube 302. The protruding portion 310 may be arranged alongthe circumferential direction of the electrically insulating tube 302 tohave a circular configuration. Alternatively, the protruding portion 310may be in the form of a plurality of bumps arranged on the inner surfaceof the electrically insulating tube 302. The bumps may be equidistantlyor non-equidistantly arranged along the inner circumferential surface ofthe electrically insulating tube 302 as long as the outer surface of themagnetic metal member 9 and the inner surface of the electricallyinsulating tube 302 are in a minimum contact and simultaneously hold thehot melt adhesive 6. In other embodiments, an entirely metal made endcap 3 could be used with an insulator disposed under the hollowconductive pin to endure the high voltage.

Referring to FIG. 10, in one embodiment, the magnetic metal member 9 canhave one or more openings 91 that are circular. However, the openings 91may instead be, for example, oval, square, star shaped, etc., as long asthe contact area between the magnetic metal member 9 and the innerperipheral surface of the electrically insulating tube 302 can bereduced and the function of the magnetic metal member 9 to heat the hotmelt adhesive 6 can be performed. In some embodiments, the openings 91occupy about 10% to about 50% of the surface area of the magnetic metalmember 9. The opening 91 can be arranged circumferentially on themagnetic metal member 9 in an equidistantly spaced or non-equidistantlyspaced manner.

Referring to FIG. 11, in other embodiments, the magnetic metal member 9has an indentation/embossment 93 on surface facing the electricallyinsulating tube 302. The embossment is raised from the inner surface ofthe magnetic metal member 9, while the indentation is depressed underthe inner surface of the magnetic metal member 9. Theindentation/embossment reduces the contact area between the innerperipheral surface of the electrically insulating tube 302 and the outersurface of the magnetic metal member 9 while maintaining the function ofmelting and curing the hot melt adhesive 6. In sum, the surface of themagnetic metal member 9 can be configured to have openings,indentations, or embossments or any combination thereof to achieve thegoal of reducing the contact area between the inner peripheral surfaceof the electrically insulating tube 302 and the outer surface of themagnetic metal member 9. At the same time, the firm adhesion between themagnetic metal member 9 and the lamp tube 1 should be secured toaccomplish the heating and solidification of the hot melt adhesive 6.

Referring to FIG. 12, in one embodiment, the magnetic metal member 9 isa circular ring. Referring to FIG. 13, in another embodiment, themagnetic metal member 9 is a non-circular ring such as but not limitedto an oval ring. When the magnetic metal member 9 is an oval ring, theminor axis of the oval ring is slightly larger than the outer diameterof the end region of the lamp tube 1 such that the contact area of theinner peripheral surface of the electrically insulating tube 302 and theouter surface of the magnetic metal member 9 is reduced and the functionof melting and curing the hot melt adhesive 6 still performs properly.For example, the inner surface of the electrically insulating tube 302may be formed with supporting portion 313 and the magnetic metal member9 in a non-circular ring shape is seated on the supporting portion 313.Thus, the contact area of the outer surface of the magnetic metal member9 and the inner surface of the electrically insulating tube 302 could bereduced while that the function of solidifying the hot melt adhesive 6could be performed. In other embodiments, the magnetic metal member 9can be disposed on the outer surface of the end cap 3 to replace thethermal conductive member 303 as shown in FIG. 5 and to perform thefunction of heating and solidifying the hot melt adhesive 6 viaelectromagnetic induction.

Referring to FIGS. 45 to 47, in other embodiments, the magnetic metalmember 9 may be omitted. Instead, in some embodiments, the hot meltadhesive 6 has a predetermined proportion of high permeability powders65 having relative permeability ranging, for example, from about 10² toabout 10⁶. The powders can be used to replace the calcite powdersoriginally included in the hot melt adhesive 6, and in certainembodiments, a volume ratio of the high permeability powders 65 to thecalcite powders may be about 1:3˜1:1. In some embodiments, the materialof the high permeability powders 65 is one of iron, nickel, cobalt,alloy thereof, or any combination thereof; the weight percentage of thehigh permeability powders 65 with respect to the hot melt adhesive isabout 10% to about 50%; and/or the powders may have mean particle sizeof about 1 to about 30 micrometers. Such a hot melt adhesive 6 allowsthe end cap 3 and the lamp tube 1 to adhere together and be qualified ina destruction test, a torque test, and a bending test. Generallyspeaking, the bending test standard for the end cap of the LED tube lampis greater than 5 newton-meters (Nt-m), while the torque test standardis greater than 1.5 newton-meters (Nt-m). In one embodiment, upon theratio of the high permeability powders 65 to the hot melt adhesive 6 andthe magnetic flux applied, the end cap 3 and the end of the lamp tube 1secured by using the hot melt adhesive 6 are qualified in a torque testof 1.5 to 5 newton-meters (Nt-m) and a bending test of 5 to 10newton-meters (Nt-m). The induction coil 11 is first switched on andallow the high permeability powders uniformly distributed in the hotmelt adhesive 6 to be charged, and therefore allow the hot melt adhesive6 to be heated to be expansive and flowing and then solidified aftercooling. Thereby, the goal of adhering the end cap 3 onto the lamp tube1 is achieved.

Referring to FIGS. 45 to 47, the high permeability powders 65 may havedifferent distribution manners in the hot melt adhesive 6. As shown inFIG. 45, the high permeability powders 65 have mean particle size ofabout 1 to about 5 micrometers, and are distributed uniformly in the hotmelt adhesive 6. When such a hot melt adhesive 6 is coated on the innersurface of the end cap 3, though the high permeability powders 65 cannotform a closed loop due to the uniform distribution, they can still beheated due to magnetic hysteresis in the electromagnetic field, so as toheat the hot melt adhesive 6. As shown in FIG. 46, the high permeabilitypowders 65 have mean particle size of about 1 to about 5 micrometers,and are distributed randomly in the hot melt adhesive 6. When such a hotmelt adhesive 6 is coated on the inner surface of the end cap 3, thehigh permeability powders 65 form a closed loop due to the randomdistribution; they can be heated due to magnetic hysteresis or theclosed loop in the electromagnetic field, so as to heat the hot meltadhesive 6. As shown in FIG. 47, the high permeability powders 65 havemean particle size of about 5 to about 30 micrometers, and aredistributed randomly in the hot melt adhesive 6. When such a hot meltadhesive 6 is coated on the inner surface of the end cap 3, the highpermeability powders 65 form a closed loop due to the randomdistribution; they can be heated due to magnetic hysteresis or theclosed loop in the electromagnetic field, so as to heat the hot meltadhesive 6. Accordingly, depending on the adjustment of the particlesize, the distribution density and the distribution manner of the highpermeability powders 65, and the electromagnetic flux applied to the endcap 3, the heating temperature of the hot melt adhesive 6 can becontrolled. In one embodiment, the hot melt adhesive 6 is flowing andsolidified after cooling from a temperature of about 200 to about 250degrees Celsius. In another embodiment, the hot melt adhesive 6 isimmediately solidified at a temperature of about 200 to about 250degrees Celsius.

Referring to FIGS. 14 and 39, in one embodiment, an end cap 3′ has apillar 312 at one end, the top end of the pillar 312 is provided with anopening having a groove 314 of, for example 0.1±1% mm depth at theperiphery thereof for positioning a conductive lead 53 as shown in FIG.39. The conductive lead 53 passes through the opening on top of thepillar 312 and has its end bent to be disposed in the groove 314. Afterthat, a conductive metallic cap 311 covers the pillar 312 such that theconductive lead 53 is fixed between the pillar 312 and the conductivemetallic cap 311. In some embodiments, the inner diameter of theconductive metallic cap 311 is 7.56±5% mm, the outer diameter of thepillar 312 is 7.23±5% mm, and the outer diameter of the conductive lead53 is 0.5±1% mm. Nevertheless, the mentioned sizes are not limited hereonce that the conductive metallic cap 311 closely covers the pillar 312without using extra adhesives and therefore completes the electricalconnection between the power supply 5 and the conductive metallic cap311.

Referring to FIGS. 1B, 3, 12, and 13, in one embodiment, the end cap 3may have openings 304 to dissipate heat generated by the power supplymodules inside the end cap 3 so as to prevent a high temperaturecondition inside the end cap 3 that might reduce reliability. In someembodiments, the openings are in a shape of an arc; especially in ashape of three arcs with different length. In one embodiment, theopenings are in a shape of three arcs with gradually varying length. Theopenings on the end cap 3 can be in any one of the above-mentioned shapeor any combination thereof.

In other embodiments, the end cap 3 is provided with a socket (notshown) for installing the power supply module.

Referring to FIG. 17, in one embodiment, the lamp tube 1 further has adiffusion film 13 coated and bonded to the inner surface thereof so thatthe light outputted or emitted from the LED light sources 202 isdiffused by the diffusion film 13 and then pass through the lamp tube 1.The diffusion film 13 can be in form of various types, such as a coatingonto the inner surface or outer wall of the lamp tube 1, or a diffusioncoating layer (not shown) coated at the surface of each LED light source202, or a separate membrane covering the LED light source 202.

Referring again to FIG. 17, in one embodiment, when the diffusion film13 is in the form of a sheet, it covers but is not in contact with theLED light sources 202. The diffusion film 13 in the form of a sheet isusually called an optical diffusion sheet or board, usually a compositemade of mixing diffusion particles into polystyrene (PS), polymethylmethacrylate (PMMA), polyethylene terephthalate (PET), and/orpolycarbonate (PC), and/or any combination thereof. The light passingthrough such composite is diffused to expand in a wide range of spacesuch as a light emitted from a plane source, and therefore makes thebrightness of the LED tube lamp uniform.

In alternative embodiments, the diffusion film 13 is in form of anoptical diffusion coating, which is composed of any one of calciumcarbonate, halogen calcium phosphate and aluminum oxide, or anycombination thereof. When the optical diffusion coating is made from acalcium carbonate with suitable solution, an excellent light diffusioneffect and transmittance to exceed 90% can be obtained. Furthermore, thediffusion film 13 in form of an optical diffusion coating may be appliedto an outer surface of the rear end region 101 having the hot meltadhesive 6 to produce increased friction resistance between the end cap3 and the rear end region 101. Compared with an example without anyoptical diffusion coating, the rear end region 101 having the diffusionfilm 13 is beneficial, for example for preventing accidental detachmentof the end cap 3 from the lamp tube 1.

In one embodiment, the composition of the diffusion film 13 in form ofthe optical diffusion coating includes calcium carbonate, strontiumphosphate (e.g., CMS-5000, white powder), thickener, and a ceramicactivated carbon (e.g., ceramic activated carbon SW-C, which is acolorless liquid). Specifically, in one example, such an opticaldiffusion coating on the inner circumferential surface of the glass tubehas an average thickness ranging between about 20 and about 30 μm. Alight transmittance of the diffusion film 13 using this opticaldiffusion coating is about 90%. Generally speaking, the lighttransmittance of the diffusion film 13 ranges from 85% to 96%. Inaddition, this diffusion film 13 can also provide electrical isolationfor reducing risk of electric shock to a user upon breakage of the lamptube 1. Furthermore, the diffusion film 13 provides an improvedillumination distribution uniformity of the light outputted by the LEDlight sources 202 such that the light can illuminate the back of thelight sources 202 and the side edges of the bendable circuit sheet so asto avoid the formation of dark regions inside the lamp tube 1 andimprove the illumination comfort. In another possible embodiment, thelight transmittance of the diffusion film can be 92% to 94% while thethickness ranges from about 200 to about 300 μm.

In another embodiment, the optical diffusion coating can also be made ofa mixture including a calcium carbonate-based substance, some reflectivesubstances like strontium phosphate or barium sulfate, a thickeningagent, ceramic activated carbon, and deionized water. The mixture iscoated on the inner circumferential surface of the glass tube and has anaverage thickness ranging between about 20 and about 30 μm. In view ofthe diffusion phenomena in microscopic terms, light is reflected byparticles. The particle size of the reflective substance such asstrontium phosphate or barium sulfate will be much larger than theparticle size of the calcium carbonate. Therefore, adding a small amountof reflective substance in the optical diffusion coating can effectivelyincrease the diffusion effect of light.

In other embodiments, halogen calcium phosphate or aluminum oxide canalso serve as the main material for forming the diffusion film 13. Theparticle size of the calcium carbonate is, for example, about 2 to 4 μm,while the particle size of the halogen calcium phosphate and aluminumoxide are about 4 to 6 μm and 1 to 2 μm, respectively. When the lighttransmittance is required to be 85% to 92%, the average thickness forthe optical diffusion coating mainly having the calcium carbonate may beabout 20 to about 30 μm, while the average thickness for the opticaldiffusion coating mainly having the halogen calcium phosphate may beabout 25 to about 35 μm, and/or the average thickness for the opticaldiffusion coating mainly having the aluminum oxide may be about 10 toabout 15 μm. However, when the required light transmittance is up to 92%and even higher, the optical diffusion coating mainly having the calciumcarbonate, the halogen calcium phosphate, or the aluminum oxide shouldbe even thinner.

The main material and the corresponding thickness of the opticaldiffusion coating can be decided according to the place for which thelamp tube 1 is used and the light transmittance required. It is notedthat the higher the light transmittance of the diffusion film isrequired, the more apparent the grainy visual of the light sources is.

Referring to FIG. 17, the inner circumferential surface of the lamp tube1 may also be provided or bonded with a reflective film 12. Thereflective film 12 is provided around the LED light sources 202, andoccupies a portion of an area of the inner circumferential surface ofthe lamp tube 1 arranged along the circumferential direction thereof. Asshown in FIG. 17, the reflective film 12 is disposed at two sides of theLED light strip 2 extending along a circumferential direction of thelamp tube 1. The LED light strip 2 is basically in a middle position ofthe lamp tube 1 and between the two reflective films 12. The reflectivefilm 12, when viewed by a person looking at the lamp tube from the side(in the X-direction shown in FIG. 17), serves to block the LED lightsources 202, so that the person does not directly see the LED lightsources 202, thereby reducing the visual graininess effect. On the otherhand, that the lights emitted from the LED light sources 202 arereflected by the reflective film 12 facilitates the divergence anglecontrol of the LED tube lamp, so that more lights illuminate towarddirections without the reflective film 12, such that the LED tube lamphas higher energy efficiency when providing the same level ofillumination performance.

Specifically, the reflective film 12 is provided on the inner peripheralsurface of the lamp tube 1, and has an opening 12 a configured toaccommodate the LED light strip 2. The size of the opening 12 a is thesame or slightly larger than the size of the LED light strip 2. Duringassembly, the LED light sources 202 are mounted on the LED light strip 2(a bendable circuit sheet) provided on the inner surface of the lamptube 1, and then the reflective film 12 is adhered to the inner surfaceof the lamp tube 1, so that the opening 12 a of the reflective film 12correspondingly matches the LED light strip 2 in a one-to-onerelationship, and the LED light strip 2 is exposed to the outside of thereflective film 12.

In one embodiment, the reflectance of the reflective film 12 isgenerally at least greater than 85%, in some embodiments greater than90%, and in some embodiments greater than 95%, to be most effective. Inone embodiment, the reflective film 12 extends circumferentially alongthe length of the lamp tube 1 occupying about 30% to 50% of the innersurface area of the lamp tube 1. In other words, a ratio of acircumferential length of the reflective film 12 along the innercircumferential surface of the lamp tube 1 to a circumferential lengthof the lamp tube 1 is about 0.3 to 0.5. In the illustrated embodiment ofFIG. 17, the reflective film 12 is disposed substantially in the middlealong a circumferential direction of the lamp tube 1, so that the twodistinct portions or sections of the reflective film 12 disposed on thetwo sides of the LED light strip 2 are substantially equal in area. Thereflective film 12 may be made of PET with some reflective materialssuch as strontium phosphate or barium sulfate or any combinationthereof, with a thickness between about 140 μm and about 350 μm orbetween about 150 μm and about 220 μm for a more preferred effect insome embodiments. As shown in FIG. 18, in other embodiments, thereflective film 12 may be provided along the circumferential directionof the lamp tube 1 on only one side of the LED light strip 2 whileoccupying the same percentage of the inner surface area of the lamp tube1 (e.g., 15% to 25% for the one side). Alternatively, as shown in FIGS.19 and 20, the reflective film 12 may be provided without any opening,and the reflective film 12 is directly adhered or mounted to the innersurface of the lamp tube 1 and followed by mounting or fixing the LEDlight strip 2 on the reflective film 12 such that the reflective film 12positioned on one side or two sides of the LED light strip 2.

In the above mentioned embodiments, various types of the reflective film12 and the diffusion film 13 can be adopted to accomplish opticaleffects including single reflection, single diffusion, and/or combinedreflection-diffusion. For example, the lamp tube 1 may be provided withonly the reflective film 12, and no diffusion film 13 is disposed insidethe lamp tube 1, such as shown in FIGS. 19, 20, and 21.

In other embodiments, the width of the LED light strip 2 (along thecircumferential direction of the lamp tube) can be widened to occupy acircumference area of the inner circumferential surface of the lamp tube1. Since the LED light strip 2 has on its surface a circuit protectivelayer made of an ink which can reflect lights, the widened part of theLED light strip 2 functions like the reflective film 12 as mentionedabove. In some embodiments, a ratio of the length of the LED light strip2 along the circumferential direction to the circumferential length ofthe lamp tube 1 is about 0.3 to 0.5. The light emitted from the lightsources could be concentrated by the reflection of the widened part ofthe LED light strip 2.

In other embodiments, the inner surface of the glass made lamp tube maybe coated totally with the optical diffusion coating, or partially withthe optical diffusion coating (where the reflective film 12 is coatedhave no optical diffusion coating). No matter in what coating manner, insome embodiments, it is more desirable that the optical diffusioncoating be coated on the outer surface of the rear end region of thelamp tube 1 so as to firmly secure the end cap 3 with the lamp tube 1.

In the present invention, the light emitted from the light sources maybe processed with the abovementioned diffusion film, reflective film,other kinds of diffusion layer sheets, adhesive film, or any combinationthereof.

Referring again to FIG. 1B, the LED tube lamp according to someembodiments of present invention also includes an adhesive sheet 4, aninsulation adhesive sheet 7, and an optical adhesive sheet 8. The LEDlight strip 2 is fixed by the adhesive sheet 4 to an innercircumferential surface of the lamp tube 1. The adhesive sheet 4 may bebut is not limited to a silicone adhesive. The adhesive sheet 4 may bein form of several short pieces or a long piece. Various kinds of theadhesive sheet 4, the insulation adhesive sheet 7, and the opticaladhesive sheet 8 can be combined to constitute various embodiments ofthe present invention.

The insulation adhesive sheet 7 is coated on the surface of the LEDlight strip 2 that faces the LED light sources 202 so that the LED lightstrip 2 is not exposed and thus electrically insulated from the outsideenvironment. In application of the insulation adhesive sheet 7, aplurality of through holes 71 on the insulation adhesive sheet 7 arereserved to correspondingly accommodate the LED light sources 202 suchthat the LED light sources 202 are mounted in the through holes 701. Thematerial composition of the insulation adhesive sheet 7 may include, forexample vinyl silicone, hydrogen polysiloxane and aluminum oxide. Theinsulation adhesive sheet 7 has a thickness, for example, ranging fromabout 100 μm to about 140 μm (micrometers). The insulation adhesivesheet 7 having a thickness less than 100 μm typically does not producesufficient insulating effect, while the insulation adhesive sheet 7having a thickness more than 140 μm may result in material waste.

The optical adhesive sheet 8, which is a clear or transparent material,is applied or coated on the surface of the LED light source 202 in orderto ensure optimal light transmittance. After being applied to the LEDlight sources 202, the optical adhesive sheet 8 may have a granular,strip-like or sheet-like shape. The performance of the optical adhesivesheet 8 depends on its refractive index and thickness. The refractiveindex of the optical adhesive sheet 8 is in some embodiments between1.22 and 1.6. In some embodiments, it is better for the optical adhesivesheet 8 to have a refractive index being a square root of the refractiveindex of the housing or casing of the LED light source 202, or thesquare root of the refractive index of the housing or casing of the LEDlight source 202 plus or minus 15%, to contribute better lighttransmittance. The housing/casing of the LED light sources 202 is astructure to accommodate and carry the LED dies (or chips) such as a LEDlead frame 202 b as shown in FIG. 37. The refractive index of theoptical adhesive sheet 8 may range from 1.225 to 1.253. In someembodiments, the thickness of the optical adhesive sheet 8 may rangefrom 1.1 mm to 1.3 mm. The optical adhesive sheet 8 having a thicknessless than 1.1 mm may not be able to cover the LED light sources 202,while the optical adhesive sheet 8 having a thickness more than 1.3 mmmay reduce light transmittance and increases material cost.

In some embodiments, in the process of assembling the LED light sourcesto the LED light strip, the optical adhesive sheet 8 is first applied onthe LED light sources 202; then the insulation adhesive sheet 7 iscoated on one side of the LED light strip 2; then the LED light sources202 are fixed or mounted on the LED light strip 2; the other side of theLED light strip 2 being opposite to the side of mounting the LED lightsources 202 is bonded and affixed to the inner surface of the lamp tube1 by the adhesive sheet 4; finally, the end cap 3 is fixed to the endportion of the lamp tube 1, and the LED light sources 202 and the powersupply 5 are electrically connected by the LED light strip 2. As shownin the embodiment of FIG. 22, the bendable circuit sheet 2 passes thetransition region 103 to be soldered or traditionally wire-bonded withthe power supply 5, and then the end cap 3 having the structure as shownin FIG. 3 or 4 or FIG. 6 is adhered to the strengthened transitionregion 103 via methods as shown in FIG. 5 or FIG. 7, respectively toform a complete LED tube lamp.

In this embodiment, the LED light strip 2 is fixed by the adhesive sheet4 to an inner circumferential surface of the lamp tube 1, so as toincrease the light illumination angle of the LED tube lamp and broadenthe viewing angle to be greater than 330 degrees. By means of applyingthe insulation adhesive sheet 7 and the optical adhesive sheet 8,electrical insulation of the entire light strip 2 is accomplished suchthat electrical shock would not occur even when the lamp tube 1 isbroken and therefore safety could be improved.

Furthermore, the inner peripheral surface or the outer circumferentialsurface of the glass made lamp tube 1 may be covered or coated with anadhesive film (not shown) to isolate the inside from the outside of theglass made lamp tube 1 when the glass made lamp tube 1 is broken. Inthis embodiment, the adhesive film is coated on the inner peripheralsurface of the lamp tube 1. The material for the coated adhesive filmincludes, for example, methyl vinyl silicone oil, hydro silicone oil,xylene, and calcium carbonate, wherein xylene is used as an auxiliarymaterial. The xylene will be volatilized and removed when the coatedadhesive film on the inner surface of the lamp tube 1 solidifies orhardens. The xylene is mainly used to adjust the capability of adhesionand therefore to control the thickness of the coated adhesive film.

In one embodiment, the thickness of the coated adhesive film ispreferably between about 100 and about 140 micrometers (μm). Theadhesive film having a thickness being less than 100 micrometers may nothave sufficient shatterproof capability for the glass tube, and theglass tube is thus prone to crack or shatter. The adhesive film having athickness being larger than 140 micrometers may reduce the lighttransmittance and also increase material cost. The thickness of thecoated adhesive film may be between about 10 and about 800 micrometers(μm) when the shatterproof capability and the light transmittance arenot strictly demanded.

In one embodiment, the inner peripheral surface or the outercircumferential surface of the glass made lamp tube 1 is coated with anadhesive film such that the broken pieces are adhered to the adhesivefilm when the glass made lamp tube is broken. Therefore, the lamp tube 1would not be penetrated to form a through hole connecting the inside andoutside of the lamp tube 1 and thus prevents a user from touching anycharged object inside the lamp tube 1 to avoid electrical shock. Inaddition, the adhesive film is able to diffuse light and allows thelight to transmit such that the light uniformity and the lighttransmittance of the entire LED tube lamp increases. The adhesive filmcan be used in combination with the adhesive sheet 4, the insulationadhesive sheet 7 and the optical adhesive sheet 8 to constitute variousembodiments of the present invention. As the LED light strip 2 isconfigured to be a bendable circuit sheet, no coated adhesive film isthereby required.

Furthermore, the light strip 2 may be an elongated aluminum plate, FR 4board, or a bendable circuit sheet. When the lamp tube 1 is made ofglass, adopting a rigid aluminum plate or FR4 board would make a brokenlamp tube, e.g., broken into two parts, remain a straight shape so thata user may be under a false impression that the LED tube lamp is stillusable and fully functional, and it is easy for him to incur electricshock upon handling or installation of the LED tube lamp. Because ofadded flexibility and bendability of the flexible substrate for the LEDlight strip 2, the problem faced by the aluminum plate, FR4 board, orconventional 3-layered flexible board having inadequate flexibility andbendability, are thereby addressed. In certain embodiments, a bendablecircuit sheet is adopted as the LED light strip 2 for that such a LEDlight strip 2 would not allow a ruptured or broken lamp tube to maintaina straight shape and therefore instantly inform the user of thedisability of the LED tube lamp and avoid possibly incurred electricalshock. The following are further descriptions of the bendable circuitsheet used as the LED light strip 2.

Referring to FIG. 23, in one embodiment, the LED light strip 2 includesa bendable circuit sheet having a conductive wiring layer 2 a and adielectric layer 2 b that are arranged in a stacked manner, wherein thewiring layer 2 a and the dielectric layer 2 b have same areas. The LEDlight source 202 is disposed on one surface of the wiring layer 2 a, thedielectric layer 2 b is disposed on the other surface of the wiringlayer 2 a that is away from the LED light sources 202. The wiring layer2 a is electrically connected to the power supply 5 to carry directcurrent (DC) signals. Meanwhile, the surface of the dielectric layer 2 baway from the wiring layer 2 a is fixed to the inner circumferentialsurface of the lamp tube 1 by means of the adhesive sheet 4. The wiringlayer 2 a can be a metal layer or a power supply layer including wiressuch as copper wires.

In another embodiment, the outer surface of the wiring layer 2 a or thedielectric layer 2 b may be covered with a circuit protective layer madeof an ink with function of resisting soldering and increasingreflectivity. Alternatively, the dielectric layer can be omitted and thewiring layer can be directly bonded to the inner circumferential surfaceof the lamp tube, and the outer surface of the wiring layer 2 a iscoated with the circuit protective layer. Whether the wiring layer 2 ahas a one-layered, or two-layered structure, the circuit protectivelayer can be adopted. In some embodiments, the circuit protective layeris disposed only on one side/surface of the LED light strip 2, such asthe surface having the LED light source 202. In some embodiments, thebendable circuit sheet is a one-layered structure made of just onewiring layer 2 a, or a two-layered structure made of one wiring layer 2a and one dielectric layer 2 b, and thus is more bendable or flexible tocurl when compared with the conventional three-layered flexiblesubstrate (one dielectric layer sandwiched with two wiring layers). As aresult, the bendable circuit sheet of the LED light strip 2 can beinstalled in a lamp tube with a customized shape or non-tubular shape,and fitly mounted to the inner surface of the lamp tube. The bendablecircuit sheet closely mounted to the inner surface of the lamp tube ispreferable in some cases. In addition, using fewer layers of thebendable circuit sheet improves the heat dissipation and lowers thematerial cost.

Nevertheless, the bendable circuit sheet is not limited to beingone-layered or two-layered; in other embodiments, the bendable circuitsheet may include multiple layers of the wiring layers 2 a and multiplelayers of the dielectric layers 2 b, in which the dielectric layers 2 band the wiring layers 2 a are sequentially stacked in a staggeredmanner, respectively. These stacked layers are away from the surface ofthe outermost wiring layer 2 a which has the LED light source 202disposed thereon and is electrically connected to the power supply 5.Moreover, the length of the bendable circuit sheet is greater than thelength of the lamp tube.

Referring to FIG. 48, in one embodiment, the LED light strip 2 includesa bendable circuit sheet having in sequence a first wiring layer 2 a, adielectric layer 2 b, and a second wiring layer 2 c. The thickness ofthe second wiring layer 2 c is greater than that of the first wiringlayer 2 a, and the length of the LED light strip 2 is greater than thatof the lamp tube 1. The end region of the light strip 2 extending beyondthe end portion of the lamp tube 1 without disposition of the lightsource 202 is formed with two separate through holes 203 and 204 torespectively electrically communicate the first wiring layer 2 a and thesecond wiring layer 2 c. The through holes 203 and 204 are notcommunicated to each other to avoid short.

In this way, the greater thickness of the second wiring layer 2 c allowsthe second wiring layer 2 c to support the first wiring layer 2 a andthe dielectric layer 2 b, and meanwhile allow the LED light strip 2 tobe mounted onto the inner circumferential surface without being liableto shift or deform, and thus the yield rate of product can be improved.In addition, the first wiring layer 2 a and the second wiring layer 2 care in electrical communication such that the circuit layout of thefirst wiring later 2 a can be extended downward to the second wiringlayer 2 c to reach the circuit layout of the entire LED light strip 2.Moreover, since the land for the circuit layout becomes two-layered, thearea of each single layer and therefore the width of the LED light strip2 can be reduced such that more LED light strips 2 can be put on aproduction line to increase productivity.

Furthermore, the first wiring layer 2 a and the second wiring layer 2 cof the end region of the LED light strip 2 that extends beyond the endportion of the lamp tube 1 without disposition of the light source 202can be used to accomplish the circuit layout of a power supply module sothat the power supply module can be directly disposed on the bendablecircuit sheet of the LED light strip 2.

Referring to FIG. 1B, in one embodiment, the LED light strip 2 has aplurality of LED light sources 202 mounted thereon, and the end cap 3has a power supply 5 installed therein. The LED light sources 202 andthe power supply 5 are electrically connected by the LED light strip 2.The power supply 5 may be a single integrated unit (i.e., all of thepower supply components are integrated into one module unit) installedin one end cap 3. Alternatively, the power supply 5 may be divided intotwo separate units (i.e. the power supply components are divided intotwo parts) installed in two end caps 3, respectively. When only one endof the lamp tube 1 is strengthened by a glass tempering process, it maybe preferable that the power supply 5 is a single integrated unit andinstalled in the end cap 3 corresponding to the strengthened end of thelamp tube 1.

The power supply 5 can be fabricated by various ways. For example, thepower supply 5 may be an encapsulation body formed by injection moldinga silica gel with high thermal conductivity such as being greater than0.7 w/m·k. This kind of power supply has advantages of high electricalinsulation, high heat dissipation, and regular shape to match othercomponents in an assembly. Alternatively, the power supply 5 in the endcaps may be a printed circuit board having components that are directlyexposed or packaged by a heat shrink sleeve. The power supply 5according to some embodiments of the present invention can be a singleprinted circuit board provided with a power supply module as shown inFIG. 23 or a single integrated unit as shown in FIG. 38.

Referring to FIGS. 1B and 38, in one embodiment of the presentinvention, the power supply 5 is provided with a male plug 51 at one endand a metal pin 52 at the other end, one end of the LED light strip 2 iscorrespondingly provided with a female plug 201, and the end cap 3 isprovided with a hollow conductive pin 301 to be connected with an outerelectrical power source. Specifically, the male plug 51 is fittinglyinserted into the female plug 201 of the LED light strip 2, while themetal pins 52 are fittingly inserted into the hollow conductive pins 301of the end cap 3. The male plug 51 and the female plug 201 function as aconnector between the power supply 5 and the LED light strip 2. Uponinsertion of the metal pin 502, the hollow conductive pin 301 is punchedwith an external punching tool to slightly deform such that the metalpin 502 of the power supply 5 is secured and electrically connected tothe hollow conductive pin 301. Upon turning on the electrical power, theelectrical current passes in sequence through the hollow conductive pin301, the metal pin 502, the male plug 501, and the female plug 201 toreach the LED light strip 2 and go to the LED light sources 202.However, the power supply 5 of the present invention is not limited tothe modular type as shown in FIG. 38. The power supply 5 may be aprinted circuit board provided with a power supply module andelectrically connected to the LED light strip 2 via the abovementionedthe male plug 51 and female plug 52 combination.

In another embodiment, a traditional wire bonding technique can be usedinstead of the male plug 51 and the female plug 52 for connecting anykind of the power supply 5 and the light strip 2. Furthermore, the wiresmay be wrapped with an electrically insulating tube to protect a userfrom being electrically shocked. However, the bonded wires tend to beeasily broken during transportation and can therefore cause qualityissues.

In still another embodiment, the connection between the power supply 5and the LED light strip 2 may be accomplished via tin soldering, rivetbonding, or welding. One way to secure the LED light strip 2 is toprovide the adhesive sheet 4 at one side thereof and adhere the LEDlight strip 2 to the inner surface of the lamp tube 1 via the adhesivesheet 4. Two ends of the LED light strip 2 can be either fixed to ordetached from the inner surface of the lamp tube 1.

In case that two ends of the LED light strip 2 are fixed to the innersurface of the lamp tube 1, it may be preferable that the bendablecircuit sheet of the LED light strip 2 is provided with the female plug201 and the power supply is provided with the male plug 51 to accomplishthe connection between the LED light strip 2 and the power supply 5. Inthis case, the male plug 51 of the power supply 5 is inserted into thefemale plug 201 to establish electrical connection.

In case that two ends of the LED light strip 2 are detached from theinner surface of the lamp tube and that the LED light strip 2 isconnected to the power supply 5 via wire-bonding, any movement insubsequent transportation is likely to cause the bonded wires to break.Therefore, a preferable option for the connection between the lightstrip 2 and the power supply 5 could be soldering. Specifically,referring to FIG. 22, the ends of the LED light strip 2 including thebendable circuit sheet are arranged to pass over the strengthenedtransition region 103 and directly soldering bonded to an outputterminal of the power supply 5 such that the product quality is improvedwithout using wires. In this way, the female plug 201 and the male plug51 respectively provided for the LED light strip 2 and the power supply5 are no longer needed.

Referring to FIG. 24, an output terminal of the printed circuit board ofthe power supply 5 may have soldering pads “a” provided with an amountof tin solder with a thickness sufficient to later form a solder joint.Correspondingly, the ends of the LED light strip 2 may have solderingpads “b”. The soldering pads “a” on the output terminal of the printedcircuit board of the power supply 5 are soldered to the soldering pads“b” on the LED light strip 2 via the tin solder on the soldering pads“a”. The soldering pads “a” and the soldering pads “b” may be face toface during soldering such that the connection between the LED lightstrip 2 and the printed circuit board of the power supply 5 is the mostfirm. However, this kind of soldering typically includes that athermo-compression head presses on the rear surface of the LED lightstrip 2 and heats the tine solder, i.e. the LED light strip 2 intervenesbetween the thermo-compression head and the tin solder, and thereforemay easily cause reliability problems. Referring to FIG. 30, a throughhole may be formed in each of the soldering pads “b” on the LED lightstrip 2 to allow the soldering pads “b” overlay the soldering pads “b”without face-to-face and the thermo-compression head directly pressestin solders on the soldering pads “a” on surface of the printed circuitboard of the power supply 5 when the soldering pads “a” and thesoldering pads “b” are vertically aligned. This is an easy way toaccomplish in practice.

Referring again to FIG. 24, two ends of the LED light strip 2 detachedfrom the inner surface of the lamp tube 1 are formed as freely extendingportions 21, while most of the LED light strip 2 is attached and securedto the inner surface of the lamp tube 1. One of the freely extendingportions 21 has the soldering pads “b” as mentioned above. Uponassembling of the LED tube lamp, the freely extending end portions 21along with the soldered connection of the printed circuit board of thepower supply 5 and the LED light strip 2 would be coiled, curled up ordeformed to be fittingly accommodated inside the lamp tube 1. When thebendable circuit sheet of the LED light strip 2 includes in sequence thefirst wiring layer 2 a, the dielectric layer 2 b, and the second wiringlayer 2 c as shown in FIG. 48, the freely extending end portions 21 canbe used to accomplish the connection between the first wiring layer 2 aand the second wiring layer 2 c and arrange the circuit layout of thepower supply 5.

In this embodiment, during the connection of the LED light strip 2 andthe power supply 5, the soldering pads “b” and the soldering pads “a”and the LED light sources 202 are on surfaces facing toward the samedirection and the soldering pads “b” on the LED light strip 2 are eachformed with a through hole “e” as shown in FIG. 30 such that thesoldering pads “b” and the soldering pads “a” communicate with eachother via the through holes “e”. When the freely extending end portions21 are deformed due to contraction or curling up, the solderedconnection of the printed circuit board of the power supply 5 and theLED light strip 2 exerts a lateral tension on the power supply 5.Furthermore, the soldered connection of the printed circuit board of thepower supply 5 and the LED light strip 2 also exerts a downward tensionon the power supply 5 when compared with the situation where thesoldering pads “a” of the power supply 5 and the soldering pads “b” ofthe LED light strip 2 are face to face. This downward tension on thepower supply 5 comes from the tin solders inside the through holes “e”and forms a stronger and more secure electrical connection between theLED light strip 2 and the power supply 5.

Referring to FIG. 25, in one embodiment, the soldering pads “b” of theLED light strip 2 are two separate pads to electrically connect thepositive and negative electrodes of the bendable circuit sheet of theLED light strip 2, respectively. The size of the soldering pads “b” maybe, for example, about 3.5×2 mm². The printed circuit board of the powersupply 5 is correspondingly provided with soldering pads “a” havingreserved tin solders, and the height of the tin solders suitable forsubsequent automatic soldering bonding process is generally, forexample, about 0.1 to 0.7 mm, in some preferable embodiments about 0.3to about 0.5 mm, and in some even more preferable embodiments about 0.4mm. An electrically insulating through hole “c” may be formed betweenthe two soldering pads “b” to isolate and prevent the two soldering padsfrom electrically short during soldering. Furthermore, an extrapositioning opening “d” may also be provided behind the electricallyinsulating through hole “c” to allow an automatic soldering machine toquickly recognize the position of the soldering pads “b”.

For the sake of achieving scalability and compatibility, the amount ofthe soldering pads “b” on each end of the LED light strip 2 may be morethan one such as two, three, four, or more than four. When there is onlyone soldering pad “b” provided at each end of the LED light strip 2, thetwo ends of the LED light strip 2 are electrically connected to thepower supply 5 to form a loop, and various electrical components can beused. For example, a capacitance may be replaced by an inductance toperform current regulation. Referring to FIGS. 26 to 28, when each endof the LED light strip 2 has three soldering pads, the third solderingpad can be grounded; when each end of the LED light strip 2 has foursoldering pads, the fourth soldering pad can be used as a signal inputterminal. Correspondingly, in some embodiments, the power supply 5should have same amount of soldering pads “a” as that of the solderingpads “b” on the LED light strip 2. In some embodiments, as long aselectrical short between the soldering pads “b” can be prevented, thesoldering pads “b” should be arranged according to the dimension of theactual area for disposition, for example, three soldering pads can bearranged in a row or two rows. In other embodiments, the amount of thesoldering pads “b” on the bendable circuit sheet of the LED light strip2 may be reduced by rearranging the circuits on the bendable circuitsheet of the LED light strip 2. The lesser the amount of the solderingpads, the easier the fabrication process becomes. On the other hand, agreater number of soldering pads may improve and secure the electricalconnection between the LED light strip 2 and the output terminal of thepower supply 5.

Referring to FIG. 30, in another embodiment, the soldering pads “b” eachis formed with a through hole “e” having a diameter generally of about 1to 2 mm, in some preferred embodiments of about 1.2 to 1.8 mm, and inyet further preferred embodiments of about 1.5 mm. The through hole “e”communicates the soldering pad “a” with the soldering pad “b” so thatthe tin solder on the soldering pads “a” passes through the throughholes “e” and finally reach the soldering pads “b”. A smaller throughhole “e” would make it difficult for the tin solder to pass. The tinsolder accumulates around the through holes “e” upon exiting the throughholes “e” and condense to form a solder ball “g” with a larger diameterthan that of the through holes “e” upon condensing. Such a solder ball“g” functions as a rivet to further increase the stability of theelectrical connection between the soldering pads “a” on the power supply5 and the soldering pads “b” on the LED light strip 2.

Referring to FIGS. 31 to 32, in other embodiments, when a distance fromthe through hole “e” to the side edge of the LED light strip 2 is lessthan 1 mm, the tin solder may pass through the through hole “e” toaccumulate on the periphery of the through hole “e”, and extra tinsolder may spill over the soldering pads “b” to reflow along the sideedge of the LED light strip 2 and join the tin solder on the solderingpads “a” of the power supply 5. The tin solder then condenses to form astructure like a rivet to firmly secure the LED light strip 2 onto theprinted circuit board of the power supply 5 such that reliable electricconnection is achieved. Referring to FIGS. 33 and 34, in anotherembodiment, the through hole “e” can be replaced by a notch “f” formedat the side edge of the soldering pads “b” for the tin solder to easilypass through the notch “f” and accumulate on the periphery of the notch“f” and to form a solder ball with a larger diameter than that of thenotch “e” upon condensing. Such a solder ball may be formed like aC-shape rivet to enhance the secure capability of the electricallyconnecting structure.

The abovementioned through hole “e” or notch “f” might be formed inadvance of soldering or formed by direct punching with athermo-compression head, as shown in FIG. 40, during soldering. Theportion of the thermo-compression head for touching the tin solder maybe flat, concave, or convex, or any combination thereof. The portion ofthe thermo-compression head for restraining the object to be solderedsuch as the LED light strip 2 may be strip-like or grid-like. Theportion of the thermo-compression head for touching the tin solder doesnot completely cover the through hole “e” or the notch “f” to make surethat the tin solder is able to pass through the through hole “e” or thenotch “f”. The portion of the thermo-compression head being concave mayfunction as a room to receive the solder ball.

Referring to FIG. 40, a thermo-compression head 41 used for bonding thesoldering pads “a” on the power supply 5 and the soldering pads “b” onthe light strip 2 is mainly composed of four sections: a bonding plane411, a plurality of concave guiding tanks 412, a plurality of concavemolding tanks 413, and a restraining plane 414. The bonding plane 411 isa portion actually touching, pressing and heating the tin solder toperform soldering bonding. The bonding plane 411 may be flat, concave,convex or any combination thereof. The concave guiding tanks 412 areformed on the bonding plane 411 and opened near an edge of the bondingplane 411 to guide the heated and melted tin solder to flow into thethrough holes or notches formed on the soldering pads. For example, theguiding tanks 412 may function to guide and stop the melted tin solders.The concave molding tanks 413 are positioned beside the guiding tanks412 and have a concave portion more depressed than that of the guidingtanks 412 such that the concave molding tanks 413 each form a housing toreceive the solder ball. The restraining plane 414 is a portion next tothe bonding plane 411 and formed with the concave molding tanks 413. Therestraining plane 414 is lower than the bonding plane 411 such that therestraining plane 414 firmly presses the LED light strip 2 on theprinted circuit board of the power supply 5 while the bonding plane 411presses against the soldering pads “b” during the soldering bonding. Therestraining plane 414 may be strip-like or grid-like on surface. Thedifference of height of the bonding plane 411 and the restraining plane414 is the thickness of the LED light strip 2.

Referring to FIGS. 41, 25, and 40, soldering pads corresponding to thesoldering pads of the LED light strip are formed on the printed circuitboard of the power supply 5 and tin solder is reserved on the solderingpads on the printed circuit board of the power supply 5 for subsequentsoldering bonding performed by an automatic soldering bonding machine.The tin solder in some embodiments has a thickness of about 0.3 mm toabout 0.5 mm such that the LED light strip 2 can be firmly soldered tothe printed circuit board of the power supply 5. As shown in FIG. 41, incase of having height difference between two tin solders respectivelyreserved on two soldering pads on the printed circuit board of the powersupply 5, the higher one will be touched first and melted by thethermo-compression head 41 while the other one will be touched and startto melt until the higher one is melted to a height the same as theheight of the other one. This usually incurs unsecured soldering bondingfor the reserved tin solder with smaller height, and therefore affectsthe electrical connection between the LED light strip 2 and the printedcircuit board of the power supply 5. To alleviate this problem, in oneembodiment, the present invention applies the kinetic equilibriumprincipal and installs a linkage mechanism on the thermo-compressionhead 41 to allow rotation of the thermo-compression head 41 during asoldering bonding such that the thermo-compression head 41 starts toheat and melt the two reserved tin solders only when thethermo-compression head 41 detects that the pressure on the two reservedtin solders are the same.

In the abovementioned embodiment, the thermo-compression head 41 isrotatable while the LED light strip 2 and the printed circuit board ofthe power supply 5 remain unmoved. Referring to FIG. 42, in anotherembodiment, the thermo-compression head 41 is unmoved while the LEDlight strip is allowed to rotate. In this embodiment, the LED lightstrip 2 and the printed circuit board of the power supply 5 are loadedon a soldering vehicle 60 including a rotary platform 61, a vehicleholder 62, a rotating shaft 63, and two elastic members 64. The rotaryplatform 61 functions to carry the LED light strip 2 and the printedcircuit board of the power supply 5. The rotary platform 61 is movablymounted to the vehicle holder 62 via the rotating shaft 63 so that therotary platform 61 is able to rotate with respect to the vehicle holder62 while the vehicle holder 62 bears and holds the rotary platform 61.The two elastic members 64 are disposed on two sides of the rotatingshaft 63, respectively, such that the rotary platform 61 in connectionwith the rotating shaft 63 always remains at the horizontal level whenthe rotary platform 61 is not loaded. In this embodiment, the elasticmembers 64 are springs for example, and the ends thereof are disposedcorresponding to two sides of the rotating shaft 63 so as to function astwo pivots on the vehicle holder 62. As shown in FIG. 42, when two tinsolders reserved on the LED light strip 2 pressed by thethermo-compression head 41 are not at the same height level, the rotaryplatform 61 carrying the LED light strip 2 and the printed circuit boardof the power supply 5 will be driven by the a rotating shaft 63 torotate until the thermo-compression head 41 detects the same pressure onthe two reserved tin solders, and then starts a soldering bonding.Referring to FIG. 43, when the rotary platform 61 rotates, the elasticmembers 64 at two sides of the rotating shaft 63 are compressed orpulled; and the driving force of the rotating shaft 63 releases and therotary platform 61 returns to the original height level by theresilience of the elastic members 64 when the soldering bonding iscompleted.

In other embodiments, the rotary platform 61 may be designed to havemechanisms without using the rotating shaft 63 and the elastic members64. For example, the rotary platform 61 may be designed to have drivingmotors and active rotary mechanisms, and therefore the vehicle holder 62is saved. Accordingly, other embodiments utilizing the kineticequilibrium principle to drive the LED light strip 2 and the printedcircuit board of the power supply 5 to move in order to complete thesoldering bonding process are within the spirit of the presentinvention.

Referring to FIGS. 35 and 36, in another embodiment, the LED light strip2 and the power supply 5 may be connected by utilizing a circuit boardassembly 25 instead of soldering bonding. The circuit board assembly 25has a long circuit sheet 251 and a short circuit board 253 that areadhered to each other with the short circuit board 253 being adjacent tothe side edge of the long circuit sheet 251. The short circuit board 253may be provided with power supply module 250 to form the power supply 5.The short circuit board 253 is stiffer or more rigid than the longcircuit sheet 251 to be able to support the power supply module 250.

The long circuit sheet 251 may be the bendable circuit sheet of the LEDlight strip including a wiring layer 2 a as shown in FIG. 23. The wiringlayer 2 a of the long circuit sheet 251 and the power supply module 250may be electrically connected in various manners depending on the demandin practice. As shown in FIG. 35, the power supply module 250 and thelong circuit sheet 251 having the wiring layer 2 a on surface are on thesame side of the short circuit board 253 such that the power supplymodule 250 is directly connected to the long circuit sheet 251. As shownin FIG. 36, alternatively, the power supply module 250 and the longcircuit sheet 251 including the wiring layer 2 a on surface are onopposite sides of the short circuit board 253 such that the power supplymodule 250 is directly connected to the short circuit board 253 andindirectly connected to the wiring layer 2 a of the LED light strip 2 byway of the short circuit board 253.

As shown in FIG. 35, in one embodiment, the long circuit sheet 251 andthe short circuit board 253 are adhered together first, and the powersupply module 250 is subsequently mounted on the wiring layer 2 a of thelong circuit sheet 251 serving as the LED light strip 2. The longcircuit sheet 251 of the LED light strip 2 herein is not limited toinclude only one wiring layer 2 a and may further include another wiringlayer such as the wiring layer 2 c shown in FIG. 48. The light sources202 are disposed on the wiring layer 2 a of the LED light strip 2 andelectrically connected to the power supply 5 by way of the wiring layer2 a. As shown in FIG. 36, in another embodiment, the long circuit sheet251 of the LED light strip 2 may include a wiring layer 2 a and adielectric layer 2 b. The dielectric layer 2 b may be adhered to theshort circuit board 253 first and the wiring layer 2 a is subsequentlyadhered to the dielectric layer 2 b and extends to the short circuitboard 253. All these embodiments are within the scope of applying thecircuit board assembly concept of the present invention.

In the above-mentioned embodiments, the short circuit board 253 may havea length generally of about 15 mm to about 40 mm and in some preferableembodiments about 19 mm to about 36 mm, while the long circuit sheet 251may have a length generally of about 800 mm to about 2800 mm and in someembodiments of about 1200 mm to about 2400 mm. A ratio of the length ofthe short circuit board 253 to the length of the long circuit sheet 251ranges from, for example, about 1:20 to about 1:200.

When the ends of the LED light strip 2 are not fixed on the innersurface of the lamp tube 1, the connection between the LED light strip 2and the power supply 5 via soldering bonding could not firmly supportthe power supply 5, and it may be necessary to dispose the power supply5 inside the end cap 3. For example, a longer end cap to have enoughspace for receiving the power supply 5 would be needed. However, thiswill reduce the length of the lamp tube under the prerequisite that thetotal length of the LED tube lamp is fixed according to the productstandard, and may therefore decrease the effective illuminating areas.

Referring to FIG. 39, in one embodiment, a hard circuit board 22 made ofaluminum is used instead of the bendable circuit sheet, such that theends or terminals of the hard circuit board 22 can be mounted at ends ofthe lamp tube 1, and the power supply 5 is solder bonded to one of theends or terminals of the hard circuit board 22 in a manner such that theprinted circuit board of the power supply 5 is not parallel but may beperpendicular to the hard circuit board 22 to save space in thelongitudinal direction used for the end cap. This solder bondingtechnique may be more convenient to accomplish and the effectiveilluminating areas of the LED tube lamp could also remain. Moreover, aconductive lead 53 for electrical connection with the end cap 3 could beformed directly on the power supply 5 without soldering other metalwires between the power supply 5 and the hollow conductive pin 301 asshown in FIG. 3, and which facilitates the manufacturing of the LED tubelamp.

Next, examples of the circuit design and using of the power supplymodule 250 are described as follows.

FIG. 49A is a block diagram of a power supply module 250 in an LED tubelamp according to an embodiment of the present invention. Referring toFIG. 49A, an AC power supply 508 is used to supply an AC supply signal,and may be an AC powerline with a voltage rating, for example, in100-277 volts and a frequency rating, for example, of 50 or 60 Hz. Alamp driving circuit 505 receives and then converts the AC supply signalinto an AC driving signal as an external driving signal. Lamp drivingcircuit 505 may be for example an electronic ballast used to convert theAC powerline into a high-frequency high-voltage AC driving signal.Common types of electronic ballast include instant-start ballast,program-start or rapid-start ballast, etc., which may all be applicableto the LED tube lamp of the present invention. The voltage of the ACdriving signal is likely higher than 300 volts, and is in someembodiments in the range of about 400-700 volts. The frequency of the ACdriving signal is likely higher than 10 k Hz, and is in some embodimentsin the range of about 20 k-50 k Hz. The LED tube lamp 500 receives anexternal driving signal and is thus driven to emit light. In oneembodiment, the external driving signal comprises the AC driving signalfrom lamp driving circuit 505. In one embodiment, LED tube lamp 500 isin a driving environment in which it is power-supplied at its one endcap having two conductive pins 501 and 502, which are coupled to lampdriving circuit 505 to receive the AC driving signal. The two conductivepins 501 and 502 may be electrically connected to, either directly orindirectly, the lamp driving circuit 505.

It is worth noting that lamp driving circuit 505 may be omitted and istherefore depicted by a dotted line. In one embodiment, if lamp drivingcircuit 505 is omitted, AC power supply 508 is directly connected topins 501 and 502, which then receive the AC supply signal as an externaldriving signal.

In addition to the above use with a single-end power supply, LED tubelamp 500 may instead be used with a dual-end power supply to one pin ateach of the two ends of an LED lamp tube. FIG. 49B is a block diagram ofa power supply module 250 in an LED tube lamp according to oneembodiment of the present invention. Referring to FIG. 49B, compared tothat shown in FIG. 49A, pins 501 and 502 are respectively disposed atthe two opposite end caps of LED tube lamp 500, forming a single pin ateach end of LED tube lamp 500, with other components and their functionsbeing the same as those in FIG. 49A.

FIG. 49C is a block diagram of an LED lamp according to one embodimentof the present invention. Referring to FIG. 49C, the power supply moduleof the LED lamp summarily includes a rectifying circuit 510, a filteringcircuit 520, and an LED driving module 530. Rectifying circuit 510 iscoupled to pins 501 and 502 to receive and then rectify an externaldriving signal, so as to output a rectified signal at output terminals511 and 512. The external driving signal may be the AC driving signal orthe AC supply signal described with reference to FIGS. 49A and 49B, ormay even be a DC signal, which embodiments do not alter the LED lamp ofthe present invention. Filtering circuit 520 is coupled to the firstrectifying circuit for filtering the rectified signal to produce afiltered signal, as recited in the claims. For instance, filteringcircuit 520 is coupled to terminals 511 and 512 to receive and thenfilter the rectified signal, so as to output a filtered signal at outputterminals 521 and 522. LED driving module 530 is coupled to filteringcircuit 520, to receive the filtered signal for emitting light. Forinstance, LED driving module 530 may be a circuit coupled to terminals521 and 522 to receive the filtered signal and thereby to drive an LEDunit (not shown) in LED driving module 530 to emit light. Details ofthese operations are described in below descriptions of certainembodiments.

It is worth noting that although there are two output terminals 511 and512 and two output terminals 521 and 522 in embodiments of these Figs.,in practice the number of ports or terminals for coupling betweenrectifying circuit 510, filtering circuit 520, and LED driving module530 may be one or more depending on the needs of signal transmissionbetween the circuits or devices.

In addition, the power supply module of the LED lamp described in FIG.49C, and embodiments of the power supply module of an LED lamp describedbelow, may each be used in the LED tube lamp 500 in FIGS. 49A and 49B,and may instead be used in any other type of LED lighting structurehaving two conductive pins used to conduct power, such as LED lightbulbs, personal area lights (PAL), plug-in LED lamps with differenttypes of bases (such as types of PL-S, PL-D, PL-T, PL-L, etc.), etc.

FIG. 49D is a block diagram of a power supply module 250 in an LED tubelamp according to an embodiment of the present invention. Referring toFIG. 49D, an AC power supply 508 is used to supply an AC supply signal.A lamp driving circuit 505 receives and then converts the AC supplysignal into an AC driving signal. An LED tube lamp 500 receives an ACdriving signal from lamp driving circuit 505 and is thus driven to emitlight. In this embodiment, LED tube lamp 500 is power-supplied at itsboth end caps respectively having two pins 501 and 502 and two pins 503and 504, which are coupled to lamp driving circuit 505 to concurrentlyreceive the AC driving signal to drive an LED unit (not shown) in LEDtube lamp 500 to emit light. AC power supply 508 may be e.g. the ACpowerline, and lamp driving circuit 505 may be a stabilizer or anelectronic ballast.

FIG. 49E is a block diagram of an LED lamp according to an embodiment ofthe present invention. Referring to FIG. 49E, the power supply module ofthe LED lamp summarily includes a rectifying circuit 510, a filteringcircuit 520, an LED driving module 530, and a filtering circuit 540.Rectifying circuit 510 is coupled to pins 501 and 502 to receive andthen rectify an external driving signal conducted by pins 501 and 502.Rectifying circuit 540 is coupled to pins 503 and 504 to receive andthen rectify an external driving signal conducted by pins 503 and 504.Therefore, the power supply module of the LED lamp may include tworectifying circuits 510 and 540 configured to output a rectified signalat output terminals 511 and 512. Filtering circuit 520 is coupled toterminals 511 and 512 to receive and then filter the rectified signal,so as to output a filtered signal at output terminals 521 and 522. LEDdriving module 530 is coupled to terminals 521 and 522 to receive thefiltered signal and thereby to drive an LED unit (not shown) in LEDdriving module 530 to emit light.

The power supply module of the LED lamp in this embodiment of FIG. 49Emay be used in LED tube lamp 500 with a dual-end power supply in FIG.49D. It is worth noting that since the power supply module of the LEDlamp comprises rectifying circuits 510 and 540, the power supply moduleof the LED lamp may be used in LED tube lamp 500 with a single-end powersupply in FIGS. 49A and 49B, to receive an external driving signal (suchas the AC supply signal or the AC driving signal described above). Thepower supply module of an LED lamp in this embodiment and otherembodiments herein may also be used with a DC driving signal.

FIG. 50A is a schematic diagram of a rectifying circuit according to anembodiment of the present invention. Referring to FIG. 50A, rectifyingcircuit 610 includes rectifying diodes 611, 612, 613, and 614,configured to full-wave rectify a received signal. Diode 611 has ananode connected to output terminal 512, and a cathode connected to pin502. Diode 612 has an anode connected to output terminal 512, and acathode connected to pin 501. Diode 613 has an anode connected to pin502, and a cathode connected to output terminal 511. Diode 614 has ananode connected to pin 501, and a cathode connected to output terminal511.

When pins 501 and 502 receive an AC signal, rectifying circuit 610operates as follows. During the connected AC signal's positive halfcycle, the AC signal is input through pin 501, diode 614, and outputterminal 511 in sequence, and later output through output terminal 512,diode 611, and pin 502 in sequence. During the connected AC signal'snegative half cycle, the AC signal is input through pin 502, diode 613,and output terminal 511 in sequence, and later output through outputterminal 512, diode 612, and pin 501 in sequence. Therefore, during theconnected AC signal's full cycle, the positive pole of the rectifiedsignal produced by rectifying circuit 610 remains at output terminal511, and the negative pole of the rectified signal remains at outputterminal 512. Accordingly, the rectified signal produced or output byrectifying circuit 610 is a full-wave rectified signal.

When pins 501 and 502 are coupled to a DC power supply to receive a DCsignal, rectifying circuit 610 operates as follows. When pin 501 iscoupled to the anode of the DC supply and pin 502 to the cathode of theDC supply, the DC signal is input through pin 501, diode 614, and outputterminal 511 in sequence, and later output through output terminal 512,diode 611, and pin 502 in sequence. When pin 501 is coupled to thecathode of the DC supply and pin 502 to the anode of the DC supply, theDC signal is input through pin 502, diode 613, and output terminal 511in sequence, and later output through output terminal 512, diode 612,and pin 501 in sequence. Therefore, no matter what the electricalpolarity of the DC signal is between pins 501 and 502, the positive poleof the rectified signal produced by rectifying circuit 610 remains atoutput terminal 511, and the negative pole of the rectified signalremains at output terminal 512.

Therefore, rectifying circuit 610 in this embodiment can output orproduce a proper rectified signal regardless of whether the receivedinput signal is an AC or DC signal.

FIG. 50B is a schematic diagram of a rectifying circuit according to anembodiment of the present invention. Referring to FIG. 50B, rectifyingcircuit 710 includes rectifying diodes 711 and 712, configured tohalf-wave rectify a received signal. Diode 711 has an anode connected topin 502, and a cathode connected to output terminal 511. Diode 712 hasan anode connected to output terminal 511, and a cathode connected topin 501. Output terminal 512 may be omitted or grounded depending onactual applications.

Next, exemplary operation(s) of rectifying circuit 710 is described asfollows.

In one embodiment, during a received AC signal's positive half cycle,the electrical potential at pin 501 is higher than that at pin 502, sodiodes 711 and 712 are both in a cutoff state as being reverse-biased,making rectifying circuit 710 not outputting a rectified signal. Duringa received AC signal's negative half cycle, the electrical potential atpin 501 is lower than that at pin 502, so diodes 711 and 712 are both ina conducting state as being forward-biased, allowing the AC signal to beinput through diode 711 and output terminal 511, and later outputthrough output terminal 512, a ground terminal, or another end of theLED tube lamp not directly connected to rectifying circuit 710.Accordingly, the rectified signal produced or output by rectifyingcircuit 710 is a half-wave rectified signal.

FIG. 50C is a schematic diagram of a rectifying circuit according to anembodiment of the present invention. Referring to FIG. 50C, rectifyingcircuit 810 includes a rectifying unit 815 and a terminal adaptercircuit 541. In this embodiment, rectifying unit 815 comprises ahalf-wave rectifier circuit including diodes 811 and 812 and configuredto half-wave rectify. Diode 811 has an anode connected to an outputterminal 512, and a cathode connected to a half-wave node 819. Diode 812has an anode connected to half-wave node 819, and a cathode connected toan output terminal 511. Terminal adapter circuit 541 is coupled tohalf-wave node 819 and pins 501 and 502, to transmit a signal receivedat pin 501 and/or pin 502 to half-wave node 819. By means of theterminal adapting function of terminal adapter circuit 541, rectifyingcircuit 810 allows of two input terminals (connected to pins 501 and502) and two output terminals 511 and 512.

Next, in certain embodiments, rectifying circuit 810 operates asfollows.

During a received AC signal's positive half cycle, the AC signal may beinput through pin 501 or 502, terminal adapter circuit 541, half-wavenode 819, diode 812, and output terminal 511 in sequence, and lateroutput through another end or circuit of the LED tube lamp. During areceived AC signal's negative half cycle, the AC signal may be inputthrough another end or circuit of the LED tube lamp, and later outputthrough output terminal 512, diode 811, half-wave node 819, terminaladapter circuit 541, and pin 501 or 502 in sequence.

It's worth noting that terminal adapter circuit 541 may comprise aresistor, a capacitor, an inductor, or any combination thereof, forperforming functions of voltage/current regulation or limiting, types ofprotection, current/voltage regulation, etc. Descriptions of thesefunctions are presented below.

In practice, rectifying unit 815 and terminal adapter circuit 541 may beinterchanged in position (as shown in FIG. 50D), without altering thefunction of half-wave rectification. FIG. 50D is a schematic diagram ofa rectifying circuit according to an embodiment of the presentinvention. Referring to FIG. 50D, diode 811 has an anode connected topin 502 and diode 812 has a cathode connected to pin 501. A cathode ofdiode 811 and an anode of diode 812 are connected to half-wave node 819.Terminal adapter circuit 541 is coupled to half-wave node 819 and outputterminals 511 and 512. During a received AC signal's positive halfcycle, the AC signal may be input through another end or circuit of theLED tube lamp, and later output through output terminal 512 or 512,terminal adapter circuit 541, half-wave node 819, diode 812, and pin 501in sequence. During a received AC signal's negative half cycle, the ACsignal may be input through pin 502, diode 811, half-wave node 819,terminal adapter circuit 541, and output node 511 or 512 in sequence,and later output through another end or circuit of the LED tube lamp.

It is worth noting that terminal adapter circuit 541 in embodimentsshown in FIGS. 50C and 50D may be omitted and is therefore depicted by adotted line. If terminal adapter circuit 541 of FIG. 50C is omitted,pins 501 and 502 will be coupled to half-wave node 819. If terminaladapter circuit 541 of FIG. 50D is omitted, output terminals 511 and 512will be coupled to half-wave node 819.

Rectifying circuit 510 as shown and explained in FIGS. 50A-D canconstitute or be the rectifying circuit 540 shown in FIG. 49E, as havingpins 503 and 504 for conducting instead of pins 501 and 502.

Next, an explanation follows as to choosing embodiments and theircombinations of rectifying circuits 510 and 540, with reference to FIGS.49C and 49E.

Rectifying circuit 510 in embodiments shown in FIG. 49C may comprise therectifying circuit 610 in FIG. 50A.

Rectifying circuits 510 and 540 in embodiments shown in FIG. 49E mayeach comprise any one of the rectifying circuits in FIGS. 50A-D, andterminal adapter circuit 541 in FIGS. 50C-D may be omitted withoutaltering the rectification function needed in an LED tube lamp. Whenrectifying circuits 510 and 540 each comprise a half-wave rectifiercircuit described in FIGS. 50B-D, during a received AC signal's positiveor negative half cycle, the AC signal may be input from one ofrectifying circuits 510 and 540, and later output from the otherrectifying circuit 510 or 540. Further, when rectifying circuits 510 and540 each comprise the rectifying circuit described in FIG. 50C or 50D,or when they comprise the rectifying circuits in FIGS. 50C and 50Drespectively, only one terminal adapter circuit 541 may be needed forfunctions of voltage/current regulation or limiting, types ofprotection, current/voltage regulation, etc. within rectifying circuits510 and 540, omitting another terminal adapter circuit 541 withinrectifying circuit 510 or 540.

FIG. 51A is a schematic diagram of the terminal adapter circuitaccording to an embodiment of the present invention. Referring to FIG.51A, terminal adapter circuit 641 comprises a capacitor 642 having anend connected to pins 501 and 502, and another end connected tohalf-wave node 819. Capacitor 642 has an equivalent impedance to an ACsignal, which impedance increases as the frequency of the AC signaldecreases, and decreases as the frequency increases. Therefore,capacitor 642 in terminal adapter circuit 641 in this embodiment worksas a high-pass filter. Further, terminal adapter circuit 641 isconnected in series to an LED unit in the LED tube lamp, producing anequivalent impedance of terminal adapter circuit 641 to perform acurrent/voltage limiting function on the LED unit, thereby preventingdamaging of the LED unit by an excessive voltage across and/or currentin the LED unit. In addition, choosing the value of capacitor 642according to the frequency of the AC signal can further enhancevoltage/current regulation.

It's worth noting that terminal adapter circuit 641 may further includea capacitor 645 and/or capacitor 646. Capacitor 645 has an end connectedto half-wave node 819, and another end connected to pin 503. Capacitor646 has an end connected to half-wave node 819, and another endconnected to pin 504. For example, half-wave node 819 may be a commonconnective node between capacitors 645 and 646. And capacitor 642 actingas a current regulating capacitor is coupled to the common connectivenode and pins 501 and 502. In such a structure, series-connectedcapacitors 642 and 645 exist between one of pins 501 and 502 and pin503, and/or series-connected capacitors 642 and 646 exist between one ofpins 501 and 502 and pin 504. Through equivalent impedances ofseries-connected capacitors, voltages from the AC signal are divided.Referring to FIGS. 49E and 51A, according to ratios between equivalentimpedances of the series-connected capacitors, the voltages respectivelyacross capacitor 642 in rectifying circuit 510, filtering circuit 520,and LED driving module 530 can be controlled, making the current flowingthrough an LED module in LED driving module 530 being limited within acurrent rating, and then protecting/preventing filtering circuit 520 andLED driving module 530 from being damaged by excessive voltages.

FIG. 51B is a schematic diagram of the terminal adapter circuitaccording to an embodiment of the present invention. Referring to FIG.51B, terminal adapter circuit 741 comprises capacitors 743 and 744.Capacitor 743 has an end connected to pin 501, and another end connectedto half-wave node 819. Capacitor 744 has an end connected to pin 502,and another end connected to half-wave node 819. Compared to terminaladapter circuit 641 in FIG. 51A, terminal adapter circuit 741 hascapacitors 743 and 744 in place of capacitor 642. Capacitance values ofcapacitors 743 and 744 may be the same as each other, or may differ fromeach other depending on the magnitudes of signals to be received at pins501 and 502.

Similarly, terminal adapter circuit 741 may further comprise a capacitor745 and/or a capacitor 746, respectively connected to pins 503 and 504.Thus, each of pins 501 and 502 and each of pins 503 and 504 may beconnected in series to a capacitor, to achieve the functions of voltagedivision and other protections.

FIG. 51C is a schematic diagram of the terminal adapter circuitaccording to an embodiment of the present invention. Referring to FIG.51C, terminal adapter circuit 841 comprises capacitors 842, 843, and844. Capacitors 842 and 843 are connected in series between pin 501 andhalf-wave node 819. Capacitors 842 and 844 are connected in seriesbetween pin 502 and half-wave node 819. In such a circuit structure, ifany one of capacitors 842, 843, and 844 is shorted, there is still atleast one capacitor (of the other two capacitors) between pin 501 andhalf-wave node 819 and between pin 502 and half-wave node 819, whichperforms a current-limiting function. Therefore, in the event that auser accidentally gets an electric shock, this circuit structure willprevent an excessive current flowing through and then seriously hurtingthe body of the user.

Similarly, terminal adapter circuit 841 may further comprise a capacitor845 and/or a capacitor 846, respectively connected to pins 503 and 504.Thus, each of pins 501 and 502 and each of pins 503 and 504 may beconnected in series to a capacitor, to achieve the functions of voltagedivision and other protections.

FIG. 51D is a schematic diagram of the terminal adapter circuitaccording to an embodiment of the present invention. Referring to FIG.51D, terminal adapter circuit 941 comprises fuses 947 and 948. Fuse 947has an end connected to pin 501, and another end connected to half-wavenode 819. Fuse 948 has an end connected to pin 502, and another endconnected to half-wave node 819. With the fuses 947 and 948, when thecurrent through each of pins 501 and 502 exceeds a current rating of acorresponding connected fuse 947 or 948, the corresponding fuse 947 or948 will accordingly melt and then break the circuit to achieveovercurrent protection.

Each of the embodiments of the terminal adapter circuits as inrectifying circuits 510 and 810 coupled to pins 501 and 502 and shownand explained above can be used or included in the rectifying circuit540 shown in FIG. 49E, as when conductive pins 503 and 504 andconductive pins 501 and 502 are interchanged in position.

Capacitance values of the capacitors in the embodiments of the terminaladapter circuits shown and described above are in some embodiments inthe range, for example, of about 100 pF-100 nF. Also, a capacitor usedin embodiments may be equivalently replaced by two or more capacitorsconnected in series or parallel. For example, each of capacitors 642 and842 may be replaced by two series-connected capacitors, one having acapacitance value chosen from the range, for example of about 1.0 nF toabout 2.5 nF and which may be in some embodiments preferably 1.5 nF, andthe other having a capacitance value chosen from the range, for exampleof about 1.5 nF to about 3.0 nF, and which is in some embodiments about2.2 nF.

FIG. 52A is a block diagram of the filtering circuit according to anembodiment of the present invention. Rectifying circuit 510 is shown inFIG. 52A for illustrating its connection with other components, withoutintending filtering circuit 520 to include rectifying circuit 510.Referring to FIG. 52A, filtering circuit 520 includes a filtering unit523 coupled to rectifying output terminals 511 and 512 to receive, andto filter out ripples of, a rectified signal from rectifying circuit510, thereby outputting a filtered signal whose waveform is smootherthan the rectified signal. Filtering circuit 520 may further compriseanother filtering unit 524 coupled between a rectifying circuit and apin, which are for example rectifying circuit 510 and pin 501,rectifying circuit 510 and pin 502, rectifying circuit 540 and pin 503,or rectifying circuit 540 and pin 504. Filtering unit 524 is forfiltering of a specific frequency, in order to filter out a specificfrequency component of an external driving signal. In this embodiment ofFIG. 52A, filtering unit 524 is coupled between rectifying circuit 510and pin 501. Filtering circuit 520 may further comprise anotherfiltering unit 525 coupled between one of pins 501 and 502 and a diodeof rectifying circuit 510, or between one of pins 503 and 504 and adiode of rectifying circuit 540, for reducing or filtering outelectromagnetic interference (EMI). In this embodiment, filtering unit525 is coupled between pin 501 and a diode (not shown in FIG. 52A) ofrectifying circuit 510. Since filtering units 524 and 525 may be presentor omitted depending on actual circumstances of their uses, they aredepicted by a dotted line in FIG. 52A.

FIG. 52B is a schematic diagram of the filtering unit according to anembodiment of the present invention. Referring to FIG. 52B, filteringunit 623 includes a capacitor 625 having an end coupled to outputterminal 511 and a filtering output terminal 521 and another end coupledto output terminal 512 and a filtering output terminal 522, and isconfigured to low-pass filter a rectified signal from output terminals511 and 512, so as to filter out high-frequency components of therectified signal and thereby output a filtered signal at outputterminals 521 and 522.

FIG. 52C is a schematic diagram of the filtering unit according to anembodiment of the present invention. Referring to FIG. 52C, filteringunit 723 comprises a pi filter circuit including a capacitor 725, aninductor 726, and a capacitor 727. As is well known, a pi filter circuitlooks like the symbol π in its shape or structure. Capacitor 725 has anend connected to output terminal 511 and coupled to output terminal 521through inductor 726, and has another end connected to output terminals512 and 522. Inductor 726 is coupled between output terminals 511 and521. Capacitor 727 has an end connected to output terminal 521 andcoupled to output terminal 511 through inductor 726, and has another endconnected to output terminals 512 and 522.

As seen between output terminals 511 and 512 and output terminals 521and 522, filtering unit 723 compared to filtering unit 623 in FIG. 52Badditionally has inductor 726 and capacitor 727, which are likecapacitor 725 in performing low-pass filtering. Therefore, filteringunit 723 in this embodiment compared to filtering unit 623 in FIG. 52Bhas a better ability to filter out high-frequency components to output afiltered signal with a smoother waveform.

Inductance values of inductor 726 in the embodiment described above arechosen in some embodiments in the range of about 10 nH to about 10 mH.And capacitance values of capacitors 625, 725, and 727 in theembodiments described above are chosen in some embodiments in the range,for example, of about 100 pF to about 1 uF.

FIG. 52D is a schematic diagram of the filtering unit according to anembodiment of the present invention. Referring to FIG. 52D, filteringunit 824 includes a capacitor 825 and an inductor 828 connected inparallel. Capacitor 825 has an end coupled to pin 501, and another endcoupled to rectifying output terminal 511, and is configured tohigh-pass filter an external driving signal input at pin 501, so as tofilter out low-frequency components of the external driving signal.Inductor 828 has an end coupled to pin 501 and another end coupled torectifying output terminal 511, and is configured to low-pass filter anexternal driving signal input at pin 501, so as to filter outhigh-frequency components of the external driving signal. Therefore, thecombination of capacitor 825 and inductor 828 works to present highimpedance to an external driving signal at one or more specificfrequencies. Thus, the parallel-connected capacitor and inductor work topresent a peak equivalent impedance to the external driving signal at aspecific frequency.

Through appropriately choosing a capacitance value of capacitor 825 andan inductance value of inductor 828, a center frequency f on thehigh-impedance band may be set at a specific value given by

${f = \frac{1}{2\;}},$where L denotes inductance of inductor 828 and C denotes capacitance ofcapacitor 825. The center frequency is in some embodiments in the rangeof about 20˜30 kHz, and may be preferably about 25 kHz. And an LED lampwith filtering unit 824 is able to be certified under safety standards,for a specific center frequency, as provided by UnderwritersLaboratories (UL).

It's worth noting that filtering unit 824 may further comprise aresistor 829, coupled between pin 501 and filtering output terminal 511.In FIG. 52D, resistor 829 is connected in series to theparallel-connected capacitor 825 and inductor 828. For example, resistor829 may be coupled between pin 501 and parallel-connected capacitor 825and inductor 828, or may be coupled between filtering output terminal511 and parallel-connected capacitor 825 and inductor 828. In thisembodiment, resistor 829 is coupled between pin 501 andparallel-connected capacitor 825 and inductor 828. Further, resistor 829is configured for adjusting the quality factor (Q) of the LC circuitcomprising capacitor 825 and inductor 828, to better adapt filteringunit 824 to application environments with different quality factorrequirements. Since resistor 829 is an optional component, it isdepicted in a dotted line in FIG. 52D.

Capacitance values of capacitor 825 are in some embodiments in the rangeof about 10 nF-2 uF. Inductance values of inductor 828 are in someembodiments smaller than 2 mH, and may be preferably smaller than 1 mH.Resistance values of resistor 829 are in some embodiments larger than 50ohms, and are may be preferably larger than 500 ohms.

Besides the filtering circuits shown and described in the aboveembodiments, traditional low-pass or band-pass filters can be used asthe filtering unit in the filtering circuit in the present invention.

FIG. 52E is a schematic diagram of the filtering unit according to anembodiment of the present invention. Referring to FIG. 52E, in thisembodiment filtering unit 925 is disposed in rectifying circuit 610 asshown in FIG. 50A, and is configured for reducing the EMI(Electromagnetic interference) caused by rectifying circuit 610 and/orother circuits. In this embodiment, filtering unit 925 includes anEMI-reducing capacitor coupled between pin 501 and the anode ofrectifying diode 613, and also between pin 502 and the anode ofrectifying diode 614, to reduce the EMI associated with the positivehalf cycle of the AC driving signal received at pins 501 and 502. TheEMI-reducing capacitor of filtering unit 925 is also coupled between pin501 and the cathode of rectifying diode 611, and between pin 502 and thecathode of rectifying diode 612, to reduce the EMI associated with thenegative half cycle of the AC driving signal received at pins 501 and502. In some embodiments, rectifying circuit 610 comprises a full-wavebridge rectifier circuit including four rectifying diodes 611, 612, 613,and 614. The full-wave bridge rectifier circuit has a first filteringnode connecting an anode and a cathode respectively of two diodes 613and 611 of the four rectifying diodes 611, 612, 613, and 614, and asecond filtering node connecting an anode and a cathode respectively ofthe other two diodes 614 and 612 of the four rectifying diodes 611, 612,613, and 614. And the EMI-reducing capacitor of the filtering unit 925is coupled between the first filtering node and the second filteringnode.

Similarly, with reference to FIGS. 50C, and 51A-51C, any capacitor ineach of the circuits in FIGS. 51A-51C is coupled between pins 501 and502 (or pins 503 and 504) and any diode in FIG. 50C, so any or eachcapacitor in FIGS. 51A-51C can work as an EMI-reducing capacitor toachieve the function of reducing EMI. For example, rectifying circuit510 in FIGS. 49C and 49E may comprise a half-wave rectifier circuitincluding two rectifying diodes and having a half-wave node connectingan anode and a cathode respectively of the two rectifying diodes, andany or each capacitor in FIGS. 51A-51C may be coupled between thehalf-wave node and at least one of the first pin and the second pin. Andrectifying circuit 540 in FIG. 49E may comprise a half-wave rectifiercircuit including two rectifying diodes and having a half-wave nodeconnecting an anode and a cathode respectively of the two rectifyingdiodes, and any or each capacitor in FIGS. 51A-51C may be coupledbetween the half-wave node and at least one of the third pin and thefourth pin.

It's worth noting that the EMI-reducing capacitor in the embodiment ofFIG. 52E may also act as capacitor 825 in filtering unit 824, so that incombination with inductor 828 and the capacitor 825 performs thefunctions of reducing EMI and presenting high impedance to an externaldriving signal at specific frequencies. For example, when the rectifyingcircuit comprises a full-wave bridge rectifier circuit, capacitor 825 offiltering unit 824 may be coupled between the first filtering node andthe second filtering node of the full-wave bridge rectifier circuit.When the rectifying circuit comprises a half-wave rectifier circuit,capacitor 825 of filtering unit 824 may be coupled between the half-wavenode of the half-wave rectifier circuit and at least one of the firstpin and the second pin.

FIG. 53A is a schematic diagram of an LED module according to anembodiment of the present invention. Referring to FIG. 53A, LED module630 has an anode connected to the filtering output terminal 521, has acathode connected to the filtering output terminal 522, and comprises atleast one LED unit 632. When two or more LED units are included, theyare connected in parallel. The anode of each LED unit 632 is connectedto the anode of LED module 630 and thus output terminal 521, and thecathode of each LED unit 632 is connected to the cathode of LED module630 and thus output terminal 522. Each LED unit 632 includes at leastone LED 631. When multiple LEDs 631 are included in an LED unit 632,they are connected in series, with the anode of the first LED 631connected to the anode of this LED unit 632, and the cathode of thefirst LED 631 connected to the next or second LED 631. And the anode ofthe last LED 631 in this LED unit 632 is connected to the cathode of aprevious LED 631, with the cathode of the last LED 631 connected to thecathode of this LED unit 632.

It's worth noting that LED module 630 may produce a current detectionsignal S531 reflecting a magnitude of current through LED module 630 andused for controlling or detecting on the LED module 630.

FIG. 53B is a schematic diagram of an LED module according to anembodiment of the present invention. Referring to FIG. 53B, LED module630 has an anode connected to the filtering output terminal 521, has acathode connected to the filtering output terminal 522, and comprises atleast two LED units 732, with the anode of each LED unit 732 connectedto the anode of LED module 630, and the cathode of each LED unit 732connected to the cathode of LED module 630. Each LED unit 732 includesat least two LEDs 731 connected in the same way as described in FIG.53A. For example, the anode of the first LED 731 in an LED unit 732 isconnected to the anode of this LED unit 732, the cathode of the firstLED 731 is connected to the anode of the next or second LED 731, and thecathode of the last LED 731 is connected to the cathode of this LED unit732. Further, LED units 732 in an LED module 630 are connected to eachother in this embodiment. All of the n-th LEDs 731 respectively of theLED units 732 are connected by every anode of every n-th LED 731 in theLED units 732, and by every cathode of every n-th LED 731, where n is apositive integer. In this way, the LEDs in LED module 630 in thisembodiment are connected in the form of a mesh.

Compared to the embodiments of FIGS. 54A-54G, LED driving module 530 ofthe above embodiments includes LED module 630, but doesn't include adriving circuit for the LED module 630.

Similarly, LED module 630 in this embodiment may produce a currentdetection signal S531 reflecting a magnitude of current through LEDmodule 630 and used for controlling or detecting on the LED module 630.

In actual practice, the number of LEDs 731 included by an LED unit 732is in some embodiments in the range of 15-25, and is may be preferablyin the range of 18-22.

FIG. 53C is a plan view of a circuit layout of the LED module accordingto an embodiment of the present invention. Referring to FIG. 53C, inthis embodiment LEDs 831 are connected in the same way as described inFIG. 53B, and three LED units are assumed in LED module 630 anddescribed as follows for illustration. A positive conductive line 834and a negative conductive line 835 are to receive a driving signal, forsupplying power to the LEDs 831. For example, positive conductive line834 may be coupled to the filtering output terminal 521 of the filteringcircuit 520 described above, and negative conductive line 835 coupled tothe filtering output terminal 522 of the filtering circuit 520, toreceive a filtered signal. For the convenience of illustration, allthree of the n-th LEDs 831 respectively of the three LED units aregrouped as an LED set 833 in FIG. 53C.

Positive conductive line 834 connects the three first LEDs 831respectively of the leftmost three LED units, at the anodes on the leftsides of the three first LEDs 831 as shown in the leftmost LED set 833of FIG. 53C. Negative conductive line 835 connects the three last LEDs831 respectively of the leftmost three LED units, at the cathodes on theright sides of the three last LEDs 831 as shown in the rightmost LED set833 of FIG. 53C. And of the three LED units, the cathodes of the threefirst LEDs 831, the anodes of the three last LEDs 831, and the anodesand cathodes of all the remaining LEDs 831 are connected by conductivelines or parts 839.

For example, the anodes of the three LEDs 831 in the leftmost LED set833 may be connected together by positive conductive line 834, and theircathodes may be connected together by a leftmost conductive part 839.The anodes of the three LEDs 831 in the second leftmost LED set 833 arealso connected together by the leftmost conductive part 839, whereastheir cathodes are connected together by a second leftmost conductivepart 839. Since the cathodes of the three LEDs 831 in the leftmost LEDset 833 and the anodes of the three LEDs 831 in the second leftmost LEDset 833 are connected together by the same leftmost conductive part 839,in each of the three LED units the cathode of the first LED 831 isconnected to the anode of the next or second LED 831, with the remainingLEDs 831 also being connected in the same way. Accordingly, all the LEDs831 of the three LED units are connected to form the mesh as shown inFIG. 53B.

It's worth noting that in this embodiment the length 836 of a portion ofeach conductive part 839 that immediately connects to the anode of anLED 831 is smaller than the length 837 of another portion of eachconductive part 839 that immediately connects to the cathode of an LED831, making the area of the latter portion immediately connecting to thecathode larger than that of the former portion immediately connecting tothe anode. The length 837 may be smaller than a length 838 of a portionof each conductive part 839 that immediately connects the cathode of anLED 831 and the anode of the next LED 831, making the area of theportion of each conductive part 839 that immediately connects a cathodeand an anode larger than the area of any other portion of eachconductive part 839 that immediately connects to only a cathode or ananode of an LED 831. Due to the length differences and area differences,this layout structure improves heat dissipation of the LEDs 831.

In some embodiments, positive conductive line 834 includes a lengthwiseportion 834 a, and negative conductive line 835 includes a lengthwiseportion 835 a, which are conducive to making the LED module have apositive “+” connective portion and a negative “−” connective portion ateach of the two ends of the LED module, as shown in FIG. 53C. Such alayout structure allows for coupling any of other circuits of the powersupply module of the LED lamp, including e.g. filtering circuit 520 andrectifying circuits 510 and 540, to the LED module through the positiveconnective portion and/or the negative connective portion at each orboth ends of the LED lamp. Thus the layout structure increases theflexibility in arranging actual circuits in the LED lamp.

FIG. 53D is a plan view of a circuit layout of the LED module accordingto another embodiment of the present invention. Referring to FIG. 53D,in this embodiment LEDs 931 are connected in the same way as describedin FIG. 53A, and three LED units each including 7 LEDs 931 are assumedin LED module 630 and described as follows for illustration. A positiveconductive line 934 and a negative conductive line 935 are to receive adriving signal, for supplying power to the LEDs 931. For example,positive conductive line 934 may be coupled to the filtering outputterminal 521 of the filtering circuit 520 described above, and negativeconductive line 935 coupled to the filtering output terminal 522 of thefiltering circuit 520, to receive a filtered signal. For the convenienceof illustration, all seven LEDs 931 of each of the three LED units aregrouped as an LED set 932 in FIG. 53D. Thus there are three LED sets 932corresponding to the three LED units.

Positive conductive line 934 connects to the anode on the left side ofthe first or leftmost LED 931 of each of the three LED sets 932.Negative conductive line 935 connects to the cathode on the right sideof the last or rightmost LED 931 of each of the three LED sets 932. Ineach LED set 932, of two consecutive LEDs 931 the LED 931 on the lefthas a cathode connected by a conductive part 939 to an anode of the LED931 on the right. By such a layout, the LEDs 931 of each LED set 932 areconnected in series.

It's also worth noting that a conductive part 939 may be used to connectan anode and a cathode respectively of two consecutive LEDs 931.Negative conductive line 935 connects to the cathode of the last orrightmost LED 931 of each of the three LED sets 932. And positiveconductive line 934 connects to the anode of the first or leftmost LED931 of each of the three LED sets 932. Therefore, as shown in FIG. 53D,the length (and thus area) of the conductive part 939 is larger thanthat of the portion of negative conductive line 935 immediatelyconnecting to a cathode, which length (and thus area) is then largerthan that of the portion of positive conductive line 934 immediatelyconnecting to an anode. For example, the length 938 of the conductivepart 939 may be larger than the length 937 of the portion of negativeconductive line 935 immediately connecting to a cathode of an LED 931,which length 937 is then larger than the length 936 of the portion ofpositive conductive line 934 immediately connecting to an anode of anLED 931. Such a layout structure improves heat dissipation of the LEDs931 in LED module 630.

Positive conductive line 934 may include a lengthwise portion 934 a, andnegative conductive line 935 may include a lengthwise portion 935 a,which are conducive to making the LED module have a positive “+”connective portion and a negative “−” connective portion at each of thetwo ends of the LED module, as shown in FIG. 53D. Such a layoutstructure allows for coupling any of other circuits of the power supplymodule of the LED lamp, including e.g. filtering circuit 520 andrectifying circuits 510 and 540, to the LED module through the positiveconnective portion 934 a and/or the negative connective portion 935 a ateach or both ends of the LED lamp. Thus the layout structure increasesthe flexibility in arranging actual circuits in the LED lamp.

Further, the circuit layouts as shown in FIGS. 53C and 53D may beimplemented with a bendable circuit sheet or substrate, which may evenbe called flexible circuit board depending on its specific definitionused. For example, the bendable circuit sheet may comprise oneconductive layer where positive conductive line 834, positive lengthwiseportion 834 a, negative conductive line 835, negative lengthwise portion835 a, and conductive parts 839 shown in FIG. 53C, and positiveconductive line 934, positive lengthwise portion 934 a, negativeconductive line 935, negative lengthwise portion 935 a, and conductiveparts 939 shown in FIG. 53D are formed by the method of etching.

FIG. 53E is a plan view of a circuit layout of the LED module accordingto another embodiment of the present invention. The layout structures ofthe LED module in FIGS. 53E and 53C each correspond to the same way ofconnecting LEDs 831 as that shown in FIG. 53B, but the layout structurein FIG. 53E comprises two conductive layers, instead of only oneconductive layer for forming the circuit layout as shown in FIG. 53C.Referring to FIG. 53E, the main difference from the layout in FIG. 53Cis that positive conductive line 834 and negative conductive line 835have a lengthwise portion 834 a and a lengthwise portion 835 a,respectively, that are formed in a second conductive layer instead. Thedifference is elaborated as follows.

Referring to FIG. 53E, the bendable circuit sheet of the LED modulecomprises a first conductive layer 2 a and a second conductive layer 2 celectrically insulated from each other by a dielectric layer 2 b (notshown). Of the two conductive layers, positive conductive line 834,negative conductive line 835, and conductive parts 839 in FIG. 53E areformed in first conductive layer 2 a by the method of etching forelectrically connecting the plurality of LED components 831 e.g. in aform of a mesh, whereas positive lengthwise portion 834 a and negativelengthwise portion 835 a are formed in second conductive layer 2 c byetching for electrically connecting to (the filtering output terminalof) the filtering circuit. Further, positive conductive line 834 andnegative conductive line 835 in first conductive layer 2 a have viapoints 834 b and via points 835 b, respectively, for connecting tosecond conductive layer 2 c. And positive lengthwise portion 834 a andnegative lengthwise portion 835 a in second conductive layer 2 c havevia points 834 c and via points 835 c, respectively. Via points 834 bare positioned corresponding to via points 834 c, for connectingpositive conductive line 834 and positive lengthwise portion 834 a. Viapoints 835 b are positioned corresponding to via points 835 c, forconnecting negative conductive line 835 and negative lengthwise portion835 a. A preferable way of connecting the two conductive layers is toform a hole connecting each via point 834 b and a corresponding viapoint 834 c, and to form a hole connecting each via point 835 b and acorresponding via point 835 c, with the holes extending through the twoconductive layers and the dielectric layer in-between. And positiveconductive line 834 and positive lengthwise portion 834 a can beelectrically connected by welding metallic part(s) through theconnecting hole(s), and negative conductive line 835 and negativelengthwise portion 835 a can be electrically connected by weldingmetallic part(s) through the connecting hole(s).

Similarly, the layout structure of the LED module in FIG. 53D mayalternatively have positive lengthwise portion 934 a and negativelengthwise portion 935 a disposed in a second conductive layer, toconstitute a two-layer layout structure.

It's worth noting that the thickness of the second conductive layer of atwo-layer bendable circuit sheet is in some embodiments larger than thatof the first conductive layer, in order to reduce the voltage drop orloss along each of the positive lengthwise portion and the negativelengthwise portion disposed in the second conductive layer. Compared toa one-layer bendable circuit sheet, since a positive lengthwise portionand a negative lengthwise portion are disposed in a second conductivelayer in a two-layer bendable circuit sheet, the width (between twolengthwise sides) of the two-layer bendable circuit sheet is or can bereduced. On the same fixture or plate in a production process, thenumber of bendable circuit sheets each with a shorter width that can belaid together at most is larger than the number of bendable circuitsheets each with a longer width that can be laid together at most. Thusadopting a bendable circuit sheet with a shorter width can increase theefficiency of production of the LED module. And reliability in theproduction process, such as the accuracy of welding position whenwelding (materials on) the LED components, can also be improved, becausea two-layer bendable circuit sheet can better maintain its shape.

As a variant of the above embodiments, a type of LED tube lamp isprovided that has at least some of the electronic components of itspower supply module disposed on a light strip of the LED tube lamp. Forexample, the technique of printed electronic circuit (PEC) can be usedto print, insert, or embed at least some of the electronic componentsonto the light strip.

In one embodiment, all electronic components of the power supply moduleare disposed on the light strip. The production process may include orproceed with the following steps: preparation of the circuit substrate(e.g. preparation of a flexible printed circuit board); ink jet printingof metallic nano-ink; ink jet printing of active and passive components(as of the power supply module); drying/sintering; ink jet printing ofinterlayer bumps; spraying of insulating ink; ink jet printing ofmetallic nano-ink; ink jet printing of active and passive components (tosequentially form the included layers); spraying of surface bond pad(s);and spraying of solder resist against LED components.

In certain embodiments, if all electronic components of the power supplymodule are disposed on the light strip, electrical connection betweenterminal pins of the LED tube lamp and the light strip may be achievedby connecting the pins to conductive lines which are welded with ends ofthe light strip. In this case, another substrate for supporting thepower supply module is not required, thereby allowing of an improveddesign or arrangement in the end cap(s) of the LED tube lamp. In someembodiments, (components of) the power supply module are disposed at twoends of the light strip, in order to significantly reduce the impact ofheat generated from the power supply module's operations on the LEDcomponents. Since no substrate other than the light strip is used tosupport the power supply module in this case, the total amount ofwelding or soldering can be significantly reduced, improving the generalreliability of the power supply module.

Another case is that some of all electronic components of the powersupply module, such as some resistors and/or smaller size capacitors,are printed onto the light strip, and some bigger size components, suchas some inductors and/or electrolytic capacitors, are disposed in theend cap(s). The production process of the light strip in this case maybe the same as that described above. And in this case disposing some ofall electronic components on the light strip is conducive to achieving areasonable layout of the power supply module in the LED tube lamp, whichmay allow of an improved design in the end cap(s).

As a variant embodiment of the above, electronic components of the powersupply module may be disposed on the light strip by a method ofembedding or inserting, e.g. by embedding the components onto a bendableor flexible light strip. In some embodiments, this embedding may berealized by a method using copper-clad laminates (CCL) for forming aresistor or capacitor; a method using ink related to silkscreenprinting; or a method of ink jet printing to embed passive components,wherein an ink jet printer is used to directly print inks to constitutepassive components and related functionalities to intended positions onthe light strip. Then through treatment by ultraviolet (UV) light ordrying/sintering, the light strip is formed where passive components areembedded. The electronic components embedded onto the light stripinclude for example resistors, capacitors, and inductors. In otherembodiments, active components also may be embedded. Through embeddingsome components onto the light strip, a reasonable layout of the powersupply module can be achieved to allow of an improved design in the endcap(s), because the surface area on a printed circuit board used forcarrying components of the power supply module is reduced or smaller,and as a result the size, weight, and thickness of the resulting printedcircuit board for carrying components of the power supply module is alsosmaller or reduced. Also in this situation since welding points on theprinted circuit board for welding resistors and/or capacitors if theywere not to be disposed on the light strip are no longer used, thereliability of the power supply module is improved, in view of the factthat these welding points are most liable to (cause or incur) faults,malfunctions, or failures. Further, the length of conductive linesneeded for connecting components on the printed circuit board istherefore also reduced, which allows of a more compact layout ofcomponents on the printed circuit board and thus improving thefunctionalities of these components.

Next, methods to produce embedded capacitors and resistors are explainedas follows.

Usually, methods for manufacturing embedded capacitors employ or involvea concept called distributed or planar capacitance. The manufacturingprocess may include the following step(s). On a substrate of a copperlayer a very thin insulation layer is applied or pressed, which is thengenerally disposed between a pair of layers including a power conductivelayer and a ground layer. The very thin insulation layer makes thedistance between the power conductive layer and the ground layer veryshort. A capacitance resulting from this structure can also be realizedby a conventional technique of a plated-through hole. Basically, thisstep is used to create this structure comprising a big parallel-platecapacitor on a circuit substrate.

Of products of high electrical capacity, certain types of productsemploy distributed capacitances, and other types of products employseparate embedded capacitances. Through putting or adding a highdielectric-constant material such as barium titanate into the insulationlayer, the high electrical capacity is achieved.

A usual method for manufacturing embedded resistors employ conductive orresistive adhesive. This may include, for example, a resin to whichconductive carbon or graphite is added, which may be used as an additiveor filler. The additive resin is silkscreen printed to an objectlocation, and is then after treatment laminated inside the circuitboard. The resulting resistor is connected to other electroniccomponents through plated-through holes or microvias. Another method iscalled Ohmega-Ply, by which a two metallic layer structure of a copperlayer and a thin nickel alloy layer constitutes a layer resistorrelative to a substrate. Then through etching the copper layer andnickel alloy layer, different types of nickel alloy resistors withcopper terminals can be formed. These types of resistor are eachlaminated inside the circuit board.

In an embodiment, conductive wires/lines are directly printed in alinear layout on an inner surface of the LED glass lamp tube, with LEDcomponents directly attached on the inner surface and electricallyconnected by the conductive wires. In some embodiments, the LEDcomponents in the form of chips are directly attached over theconductive wires on the inner surface, and connective points are atterminals of the wires for connecting the LED components and the powersupply module. After being attached, the LED chips may have fluorescentpowder applied or dropped thereon, for producing white light or light ofother color by the operating LED tube lamp.

In some embodiments, luminous efficacy of the LED or LED component is 80lm/W or above, and in some embodiments, it may be preferably 120 lm/W orabove. Certain more optimal embodiments may include a luminous efficacyof the LED or LED component of 160 km/W or above. White light emitted byan LED component in the invention may be produced by mixing fluorescentpowder with the monochromatic light emitted by a monochromatic LED chip.The white light in its spectrum has major wavelength ranges of 430-460nm and 550-560 nm, or major wavelength ranges of 430-460 nm, 540-560 nm,and 620-640 nm.

FIG. 54A is a block diagram of a power supply module in an LED lampaccording to an embodiment of the present invention. As shown in FIG.54A, the power supply module of the LED lamp includes rectifyingcircuits 510 and 540, a filtering circuit 520, and an LED driving module530. LED driving module 530 in this embodiment comprises a drivingcircuit 1530 and an LED module 630. According to the above descriptionin FIG. 49E, driving circuit 1530 in FIG. 54A comprises a DC-to-DCconverter circuit, and is coupled to filtering output terminals 521 and522 to receive a filtered signal and then perform power conversion forconverting the filtered signal into a driving signal at driving outputterminals 1521 and 1522. The LED module 630 is coupled to driving outputterminals 1521 and 1522 to receive the driving signal for emittinglight. In some embodiments, the current of LED module 630 is stabilizedat an objective current value. Descriptions of this LED module 630 arethe same as those provided above with reference to FIGS. 53A-53D.

It's worth noting that rectifying circuit 540 is an optional element andtherefore can be omitted, so it is depicted in a dotted line in FIG.54A. Accordingly, LED driving module 530 in embodiments of FIGS. 54A,54C, and 54E may comprise a driving circuit 1530 and an LED module 630.Therefore, the power supply module of the LED lamp in this embodimentcan be used with a single-end power supply coupled to one end of the LEDlamp, and can be used with a dual-end power supply coupled to two endsof the LED lamp. With a single-end power supply, examples of the LEDlamp include an LED light bulb, a personal area light (PAL), etc.

FIG. 54B is a block diagram of the driving circuit according to anembodiment of the present invention. Referring to FIG. 54B, the drivingcircuit includes a controller 1531, and a conversion circuit 1532 forpower conversion based on a current source, for driving the LED moduleto emit light. Conversion circuit 1532 includes a switching circuit 1535and an energy storage circuit 1538. And conversion circuit 1532 iscoupled to filtering output terminals 521 and 522 to receive and thenconvert a filtered signal, under the control by controller 1531, into adriving signal at driving output terminals 1521 and 1522 for driving theLED module. Under the control by controller 1531, the driving signaloutput by conversion circuit 1532 comprises a steady current, making theLED module emitting steady light.

FIG. 54C is a schematic diagram of the driving circuit according to anembodiment of the present invention. Referring to FIG. 54C, a drivingcircuit 1630 in this embodiment comprises a buck DC-to-DC convertercircuit having a controller 1631 and a converter circuit. The convertercircuit includes an inductor 1632, a diode 1633 for “freewheeling” ofcurrent, a capacitor 1634, and a switch 1635. Driving circuit 1630 iscoupled to filtering output terminals 521 and 522 to receive and thenconvert a filtered signal into a driving signal for driving an LEDmodule connected between driving output terminals 1521 and 1522.

In this embodiment, switch 1635 comprises a metal-oxide-semiconductorfield-effect transistor (MOSFET) and has a first terminal coupled to theanode of freewheeling diode 1633, a second terminal coupled to filteringoutput terminal 522, and a control terminal coupled to controller 1631used for controlling current conduction or cutoff between the first andsecond terminals of switch 1635. Driving output terminal 1521 isconnected to filtering output terminal 521, and driving output terminal1522 is connected to an end of inductor 1632, which has another endconnected to the first terminal of switch 1635. Capacitor 1634 iscoupled between driving output terminals 1521 and 1522, to stabilize thevoltage between driving output terminals 1521 and 1522. Freewheelingdiode 1633 has a cathode connected to driving output terminal 1521.

Next, a description follows as to an exemplary operation of drivingcircuit 1630.

Controller 1631 is configured for determining when to turn switch 1635on (in a conducting state) or off (in a cutoff state), according to acurrent detection signal S535 and/or a current detection signal S531.For example, in some embodiments, controller 1631 is configured tocontrol the duty cycle of switch 1635 being on and switch 1635 beingoff, in order to adjust the size or magnitude of the driving signal.Current detection signal S535 represents the magnitude of currentthrough switch 1635. Current detection signal S531 represents themagnitude of current through the LED module coupled between drivingoutput terminals 1521 and 1522. According to any of current detectionsignal S535 and current detection signal S531, controller 1631 canobtain information on the magnitude of power converted by the convertercircuit. When switch 1635 is switched on, a current of a filtered signalis input through filtering output terminal 521, and then flows throughcapacitor 1634, driving output terminal 1521, the LED module, inductor1632, and switch 1635, and then flows out from filtering output terminal522. During this flowing of current, capacitor 1634 and inductor 1632are performing storing of energy. On the other hand, when switch 1635 isswitched off, capacitor 1634 and inductor 1632 perform releasing ofstored energy by a current flowing from freewheeling capacitor 1633 todriving output terminal 1521 to make the LED module continuing to emitlight.

It's worth noting that capacitor 1634 is an optional element, so it canbe omitted and is thus depicted in a dotted line in FIG. 54C. In someapplication environments, the natural characteristic of an inductor tooppose instantaneous change in electric current passing through theinductor may be used to achieve the effect of stabilizing the currentthrough the LED module, thus omitting capacitor 1634.

FIG. 54D is a schematic diagram of the driving circuit according to anembodiment of the present invention. Referring to FIG. 54D, a drivingcircuit 1730 in this embodiment comprises a boost DC-to-DC convertercircuit having a controller 1731 and a converter circuit. The convertercircuit includes an inductor 1732, a diode 1733 for “freewheeling” ofcurrent, a capacitor 1734, and a switch 1735. Driving circuit 1730 isconfigured to receive and then convert a filtered signal from filteringoutput terminals 521 and 522 into a driving signal for driving an LEDmodule coupled between driving output terminals 1521 and 1522.

Inductor 1732 has an end connected to filtering output terminal 521, andanother end connected to the anode of freewheeling diode 1733 and afirst terminal of switch 1735, which has a second terminal connected tofiltering output terminal 522 and driving output terminal 1522.Freewheeling diode 1733 has a cathode connected to driving outputterminal 1521. And capacitor 1734 is coupled between driving outputterminals 1521 and 1522.

Controller 1731 is coupled to a control terminal of switch 1735, and isconfigured for determining when to turn switch 1735 on (in a conductingstate) or off (in a cutoff state), according to a current detectionsignal S535 and/or a current detection signal S531. When switch 1735 isswitched on, a current of a filtered signal is input through filteringoutput terminal 521, and then flows through inductor 1732 and switch1735, and then flows out from filtering output terminal 522. During thisflowing of current, the current through inductor 1732 increases withtime, with inductor 1732 being in a state of storing energy, whilecapacitor 1734 enters a state of releasing energy, making the LED modulecontinuing to emit light. On the other hand, when switch 1735 isswitched off, inductor 1732 enters a state of releasing energy as thecurrent through inductor 1732 decreases with time. In this state, thecurrent through inductor 1732 then flows through freewheeling diode1733, capacitor 1734, and the LED module, while capacitor 1734 enters astate of storing energy.

It's worth noting that capacitor 1734 is an optional element, so it canbe omitted and is thus depicted in a dotted line in FIG. 54D. Whencapacitor 1734 is omitted and switch 1735 is switched on, the current ofinductor 1732 does not flow through the LED module, making the LEDmodule not emit light; but when switch 1735 is switched off, the currentof inductor 1732 flows through freewheeling diode 1733 to reach the LEDmodule, making the LED module emit light. Therefore, by controlling thetime that the LED module emits light, and the magnitude of currentthrough the LED module, the average luminance of the LED module can bestabilized to be above a defined value, thus also achieving the effectof emitting a steady light.

FIG. 54E is a schematic diagram of the driving circuit according to anembodiment of the present invention. Referring to FIG. 54E, a drivingcircuit 1830 in this embodiment comprises a buck DC-to-DC convertercircuit having a controller 1831 and a converter circuit. The convertercircuit includes an inductor 1832, a diode 1833 for “freewheeling” ofcurrent, a capacitor 1834, and a switch 1835. Driving circuit 1830 iscoupled to filtering output terminals 521 and 522 to receive and thenconvert a filtered signal into a driving signal for driving an LEDmodule connected between driving output terminals 1521 and 1522.

Switch 1835 has a first terminal coupled to filtering output terminal521, a second terminal coupled to the cathode of freewheeling diode1833, and a control terminal coupled to controller 1831 to receive acontrol signal from controller 1831 for controlling current conductionor cutoff between the first and second terminals of switch 1835. Theanode of freewheeling diode 1833 is connected to filtering outputterminal 522 and driving output terminal 1522. Inductor 1832 has an endconnected to the second terminal of switch 1835, and another endconnected to driving output terminal 1521. Capacitor 1834 is coupledbetween driving output terminals 1521 and 1522, to stabilize the voltagebetween driving output terminals 1521 and 1522.

Controller 1831 is configured for controlling when to turn switch 1835on (in a conducting state) or off (in a cutoff state), according to acurrent detection signal S535 and/or a current detection signal S531.When switch 1835 is switched on, a current of a filtered signal is inputthrough filtering output terminal 521, and then flows through switch1835, inductor 1832, and driving output terminals 1521 and 1522, andthen flows out from filtering output terminal 522. During this flowingof current, the current through inductor 1832 and the voltage ofcapacitor 1834 both increase with time, so inductor 1832 and capacitor1834 are in a state of storing energy. On the other hand, when switch1835 is switched off, inductor 1832 is in a state of releasing energyand thus the current through it decreases with time. In this case, thecurrent through inductor 1832 circulates through driving outputterminals 1521 and 1522, freewheeling diode 1833, and back to inductor1832.

It's worth noting that capacitor 1834 is an optional element, so it canbe omitted and is thus depicted in a dotted line in FIG. 54E. Whencapacitor 1834 is omitted, no matter whether switch 1835 is turned on oroff, the current through inductor 1832 will flow through driving outputterminals 1521 and 1522 to drive the LED module to continue emittinglight.

FIG. 54F is a schematic diagram of the driving circuit according to anembodiment of the present invention. Referring to FIG. 54F, a drivingcircuit 1930 in this embodiment comprises a buck DC-to-DC convertercircuit having a controller 1931 and a converter circuit. The convertercircuit includes an inductor 1932, a diode 1933 for “freewheeling” ofcurrent, a capacitor 1934, and a switch 1935. Driving circuit 1930 iscoupled to filtering output terminals 521 and 522 to receive and thenconvert a filtered signal into a driving signal for driving an LEDmodule connected between driving output terminals 1521 and 1522.

Inductor 1932 has an end connected to filtering output terminal 521 anddriving output terminal 1522, and another end connected to a first endof switch 1935. Switch 1935 has a second end connected to filteringoutput terminal 522, and a control terminal connected to controller 1931to receive a control signal from controller 1931 for controlling currentconduction or cutoff of switch 1935. Freewheeling diode 1933 has ananode coupled to a node connecting inductor 1932 and switch 1935, and acathode coupled to driving output terminal 1521. Capacitor 1934 iscoupled to driving output terminals 1521 and 1522, to stabilize thedriving of the LED module coupled between driving output terminals 1521and 1522.

Controller 1931 is configured for controlling when to turn switch 1935on (in a conducting state) or off (in a cutoff state), according to acurrent detection signal S531 and/or a current detection signal S535.When switch 1935 is turned on, a current is input through filteringoutput terminal 521, and then flows through inductor 1932 and switch1935, and then flows out from filtering output terminal 522. During thisflowing of current, the current through inductor 1932 increases withtime, so inductor 1932 is in a state of storing energy; but the voltageof capacitor 1934 decreases with time, so capacitor 1934 is in a stateof releasing energy to keep the LED module continuing to emit light. Onthe other hand, when switch 1935 is turned off, inductor 1932 is in astate of releasing energy and its current decreases with time. In thiscase, the current through inductor 1932 circulates through freewheelingdiode 1933, driving output terminals 1521 and 1522, and back to inductor1932. During this circulation, capacitor 1934 is in a state of storingenergy and its voltage increases with time.

It's worth noting that capacitor 1934 is an optional element, so it canbe omitted and is thus depicted in a dotted line in FIG. 54F. Whencapacitor 1934 is omitted and switch 1935 is turned on, the currentthrough inductor 1932 doesn't flow through driving output terminals 1521and 1522, thereby making the LED module not emit light. On the otherhand, when switch 1935 is turned off, the current through inductor 1932flows through freewheeling diode 1933 and then the LED module to makethe LED module emit light. Therefore, by controlling the time that theLED module emits light, and the magnitude of current through the LEDmodule, the average luminance of the LED module can be stabilized to beabove a defined value, thus also achieving the effect of emitting asteady light.

FIG. 54G is a block diagram of the driving circuit according to anembodiment of the present invention. Referring to FIG. 54G, the drivingcircuit includes a controller 2631, and a conversion circuit 2632 forpower conversion based on an adjustable current source, for driving theLED module to emit light. Conversion circuit 2632 includes a switchingcircuit 2635 and an energy storage circuit 2638. And conversion circuit2632 is coupled to filtering output terminals 521 and 522 to receive andthen convert a filtered signal, under the control by controller 2631,into a driving signal at driving output terminals 1521 and 1522 fordriving the LED module. Controller 2631 is configured to receive acurrent detection signal S535 and/or a current detection signal S539,for controlling or stabilizing the driving signal output by conversioncircuit 2632 to be above an objective current value. Current detectionsignal S535 represents the magnitude of current through switchingcircuit 2635. Current detection signal S539 represents the magnitude ofcurrent through energy storage circuit 2638, which current may be e.g.an inductor current in energy storage circuit 2638 or a current outputat driving output terminal 1521. Any of current detection signal S535and current detection signal S539 can represent the magnitude of currentIout provided by the driving circuit from driving output terminals 1521and 1522 to the LED module. Controller 2631 is coupled to filteringoutput terminal 521 for setting the objective current value according tothe voltage Vin at filtering output terminal 521. Therefore, the currentIout provided by the driving circuit or the objective current value canbe adjusted corresponding to the magnitude of the voltage Vin of afiltered signal output by a filtering circuit.

It's worth noting that current detection signals S535 and S539 can begenerated by measuring current through a resistor or induced by aninductor. For example, a current can be measured according to a voltagedrop across a resistor in conversion circuit 2632 the current flowsthrough, or which arises from a mutual induction between an inductor inconversion circuit 2632 and another inductor in its energy storagecircuit 2638.

The above driving circuit structures are especially suitable for anapplication environment in which the external driving circuit for theLED tube lamp includes electronic ballast. An electronic ballast isequivalent to a current source whose output power is not constant. In aninternal driving circuit as shown in each of FIGS. 54C-54F, powerconsumed by the internal driving circuit relates to or depends on thenumber of LEDs in the LED module, and could be regarded as constant.When the output power of the electronic ballast is higher than powerconsumed by the LED module driven by the driving circuit, the outputvoltage of the ballast will increase continually, causing the level ofan AC driving signal received by the power supply module of the LED lampto continually increase, so as to risk damaging the ballast and/orcomponents of the power supply module due to their voltage ratings beingexceeded. On the other hand, when the output power of the electronicballast is lower than power consumed by the LED module driven by thedriving circuit, the output voltage of the ballast and the level of theAC driving signal will decrease continually so that the LED tube lampfail to normally operate.

It's worth noting that the power needed for an LED lamp to work isalready lower than that needed for a fluorescent lamp to work. If aconventional control mechanism of e.g. using a backlight module tocontrol the LED luminance is used with a conventional driving system ofe.g. a ballast, a problem will probably arise of mismatch orincompatibility between the output power of the external driving systemand the power needed by the LED lamp. This problem may even causedamaging of the driving system and/or the LED lamp. To prevent thisproblem, using e.g. the power/current adjustment method described abovein FIG. 54G enables the LED (tube) lamp to be better compatible withtraditional fluorescent lighting system.

FIG. 54H is a graph illustrating the relationship between the voltageVin and the objective current value Iout according to an embodiment ofthe present invention. In FIG. 54H, the variable Vin is on thehorizontal axis, and the variable Iout is on the vertical axis. In somecases, when the level of the voltage Vin of a filtered signal is betweenthe upper voltage limit VH and the lower voltage limit VL, the objectivecurrent value Iout will be about an initial objective current value. Theupper voltage limit VH is higher than the lower voltage limit VL. Whenthe voltage Vin increases to be higher than the upper voltage limit VH,the objective current value Iout will increase with the increasing ofthe voltage Vin. During this stage, a situation that may be preferableis that the slope of the relationship curve increase with the increasingof the voltage Vin. When the voltage Vin of a filtered signal decreasesto be below the lower voltage limit VL, the objective current value Ioutwill decrease with the decreasing of the voltage Vin. During this stage,a situation that may be preferable is that the slope of the relationshipcurve decrease with the decreasing of the voltage Vin. For example,during the stage when the voltage Vin is higher than the upper voltagelimit VH or lower than the lower voltage limit VL, the objective currentvalue Iout is in some embodiments a function of the voltage Vin to thepower of 2 or above, in order to make the rate of increase/decrease ofthe consumed power higher than the rate of increase/decrease of theoutput power of the external driving system. Thus, adjustment of theobjective current value Iout is in some embodiments a function of thefiltered voltage Vin to the power of 2 or above.

In another case, when the voltage Vin of a filtered signal is betweenthe upper voltage limit VH and the lower voltage limit VL, the objectivecurrent value Iout of the LED lamp will vary, increase or decrease,linearly with the voltage Vin. During this stage, when the voltage Vinis at the upper voltage limit VH, the objective current value Iout willbe at the upper current limit IH. When the voltage Vin is at the lowervoltage limit VL, the objective current value Iout will be at the lowercurrent limit IL. The upper current limit IH is larger than the lowercurrent limit IL. And when the voltage Vin is between the upper voltagelimit VH and the lower voltage limit VL, the objective current valueIout will be a function of the voltage Vin to the power of 1.

With the designed relationship in FIG. 54H, when the output power of theballast is higher than the power consumed by the LED module driven bythe driving circuit, the voltage Vin will increase with time to exceedthe upper voltage limit VH. When the voltage Vin is higher than theupper voltage limit VH, the rate of increase of the consumed power ofthe LED module is higher than that of the output power of the electronicballast, and the output power and the consumed power will be balanced orequal when the voltage Vin is at a high balance voltage value VH+ andthe current Iout is at a high balance current value IH+. In this case,the high balance voltage value VH+ is larger than the upper voltagelimit VH, and the high balance current value IH+ is larger than theupper current limit IH. On the other hand, when the output power of theballast is lower than the power consumed by the LED module driven by thedriving circuit, the voltage Vin will decrease to be below the lowervoltage limit VL. When the voltage Vin is lower than the lower voltagelimit VL, the rate of decrease of the consumed power of the LED moduleis higher than that of the output power of the electronic ballast, andthe output power and the consumed power will be balanced or equal whenthe voltage Vin is at a low balance voltage value VL− and the objectivecurrent value Iout is at a low balance current value IL−. In this case,the low balance voltage value VL− is smaller than the lower voltagelimit VL, and the low balance current value IL− is smaller than thelower current limit IL.

In some embodiments, the lower voltage limit VL is defined to be around90% of the lowest output power of the electronic ballast, and the uppervoltage limit VH is defined to be around 110% of its highest outputpower. Taking a common AC powerline with a voltage range of 100-277volts and a frequency of 60 Hz as an example, the lower voltage limit VLmay be set at 90 volts (=100*90%), and the upper voltage limit VH may beset at 305 volts (=277*110%).

With reference to FIGS. 35 and 36, a short circuit board 253 includes afirst short circuit substrate and a second short circuit substraterespectively connected to two terminal portions of a long circuit sheet251, and electronic components of the power supply module arerespectively disposed on the first short circuit substrate and thesecond short circuit substrate. The first short circuit substrate andthe second short circuit substrate may have roughly the same length, ordifferent lengths. In general, the first short circuit substrate (i.e.the right circuit substrate of short circuit board 253 in FIG. 35 andthe left circuit substrate of short circuit board 253 in FIG. 36) has alength that is about 30%-80% of the length of the second short circuitsubstrate (i.e. the left circuit substrate of short circuit board 253 inFIG. 35 and the right circuit substrate of short circuit board 253 inFIG. 36). In some embodiments the length of the first short circuitsubstrate is about ⅓˜⅔ of the length of the second short circuitsubstrate. For example, in one embodiment, the length of the first shortcircuit substrate may be about half the length of the second shortcircuit substrate. The length of the second short circuit substrate maybe, for example in the range of about 15 mm to about 65 mm, depending onactual application occasions. In certain embodiments, the first shortcircuit substrate is disposed in an end cap at an end of the LED tubelamp, and the second short circuit substrate is disposed in another endcap at the opposite end of the LED tube lamp.

For example, capacitors of the driving circuit, such as capacitors 1634,1734, 1834, and 1934 in FIGS. 54C˜54F, in practical use may include twoor more capacitors connected in parallel. Some or all capacitors of thedriving circuit in the power supply module may be arranged on the firstshort circuit substrate of short circuit board 253, while othercomponents such as the rectifying circuit, filtering circuit,inductor(s) of the driving circuit, controller(s), switch(es), diodes,etc. are arranged on the second short circuit substrate of short circuitboard 253. Since inductors, controllers, switches, etc. are electroniccomponents with higher temperature, arranging some or all capacitors ona circuit substrate separate or away from the circuit substrate(s) ofhigh-temperature components helps prevent the working life of capacitors(especially electrolytic capacitors) from being negatively affected bythe high-temperature components, thus improving the reliability of thecapacitors. Further, the physical separation between the capacitors andboth the rectifying circuit and filtering circuit also contributes toreducing the problem of EMI.

In some embodiments, the driving circuit has power conversion efficiencyof 80% or above, which may preferably be 90% or above, and may even morepreferably be 92% or above. Therefore, without the driving circuit,luminous efficacy of the LED lamp according to some embodiments maypreferably be 120 lm/W or above, and may even more preferably be 160lm/W or above. On the other hand, with the driving circuit incombination with the LED component(s), luminous efficacy of the LED lampin the invention may preferably be, in some embodiments, 120lm/W*90%=108 lm/W or above, and may even more preferably be, in someembodiments 160 lm/W*92%=147.2 lm/W or above.

In view of the fact that the diffusion film or layer in an LED tube lamphas light transmittance of 85% or above, luminous efficacy of the LEDtube lamp of the invention is in some embodiments 108 lm/W*85%=91.8 lm/Wor above, and may be, in some more effective embodiments, 147.2lm/W*85%=125.12 lm/W.

FIG. 55A is a block diagram of using a power supply module in an LEDlamp according to an embodiment of the present invention. Compared toFIG. 54A, the embodiment of FIG. 55A includes rectifying circuits 510and 540, a filtering circuit 520, and an LED driving module 530, andfurther includes an anti-flickering circuit 550 coupled betweenfiltering circuit 520 and LED driving module 530. It's noted thatrectifying circuit 540 may be omitted and is thus depicted in a dottedline in FIG. 55A.

Anti-flickering circuit 550 is coupled to filtering output terminals 521and 522, to receive a filtered signal, and under specific circumstancesto consume partial energy of the filtered signal so as to reduce (theincidence of) ripples of the filtered signal disrupting or interruptingthe light emission of the LED driving module 530. In general, filteringcircuit 520 has such filtering components as resistor(s) and/orinductor(s), and/or parasitic capacitors and inductors, which may formresonant circuits. Upon breakoff or stop of an AC power signal, as whenthe power supply of the LED lamp is turned off by a user, theamplitude(s) of resonant signals in the resonant circuits will decreasewith time. But LEDs in the LED module of the LED lamp are unidirectionalconduction devices and require a minimum conduction voltage for the LEDmodule. When a resonant signal's trough value is lower than the minimumconduction voltage of the LED module, but its peak value is still higherthan the minimum conduction voltage, the flickering phenomenon willoccur in light emission of the LED module. In this case anti-flickeringcircuit 550 works by allowing a current matching a defined flickeringcurrent value of the LED component to flow through, consuming partialenergy of the filtered signal which should be higher than the energydifference of the resonant signal between its peak and trough values, soas to reduce the flickering phenomenon. In certain embodiments, apreferred occasion for anti-flickering circuit 550 to work is when thefiltered signal's voltage approaches (and is still higher than) theminimum conduction voltage.

It's worth noting that anti-flickering circuit 550 may be more suitablefor the situation in which LED driving module 530 doesn't includedriving circuit 1530, for example, when LED module 630 of LED drivingmodule 530 is (directly) driven to emit light by a filtered signal froma filtering circuit. In this case, the light emission of LED module 630will directly reflect variation in the filtered signal due to itsripples. In this situation, the introduction of anti-flickering circuit550 will prevent the flickering phenomenon from occurring in the LEDlamp upon the breakoff of power supply to the LED lamp.

FIG. 55B is a schematic diagram of the anti-flickering circuit accordingto an embodiment of the present invention. Referring to FIG. 55B,anti-flickering circuit 650 includes at least a resistor, such as tworesistors connected in series between filtering output terminals 521 and522. In this embodiment, anti-flickering circuit 650 in use consumespartial energy of a filtered signal continually. When in normaloperation of the LED lamp, this partial energy is far lower than theenergy consumed by LED driving module 530. But upon a breakoff or stopof the power supply, when the voltage level of the filtered signaldecreases to approach the minimum conduction voltage of LED module 630,this partial energy is still consumed by anti-flickering circuit 650 inorder to offset the impact of the resonant signals which may cause theflickering of light emission of LED module 630. In some embodiments, acurrent equal to or larger than an anti-flickering current level may beset to flow through anti-flickering circuit 650 when LED module 630 issupplied by the minimum conduction voltage, and then an equivalentanti-flickering resistance of anti-flickering circuit 650 can bedetermined based on the set current.

FIG. 56A is a block diagram of using a power supply module in an LEDlamp according to an embodiment of the present invention. Compared toFIG. 55A, the embodiment of FIG. 56A includes rectifying circuits 510and 540, a filtering circuit 520, an LED driving module 530, and ananti-flickering circuit 550, and further includes a protection circuit560. Protection circuit 560 is coupled to filtering output terminals 521and 522, to detect the filtered signal from filtering circuit 520 fordetermining whether to enter a protection state. Upon entering aprotection state, protection circuit 560 works to limit, restrain, orclamp down on the level of the filtered signal, preventing damaging ofcomponents in LED driving module 530. And rectifying circuit 540 andanti-flickering circuit 550 may be omitted and are thus depicted in adotted line in FIG. 56A.

FIG. 56B is a schematic diagram of the protection circuit according toan embodiment of the present invention. Referring to FIG. 56B, aprotection circuit 660 includes a voltage clamping circuit, a voltagedivision circuit, capacitors 663 and 670, resistor 669, and a diode 672,for entering a protection state when a current and/or voltage of the LEDmodule is/are or might be excessively high, thus preventing damaging ofthe LED module. The voltage clamping circuit includes a bidirectionaltriode thyristor (TRIAC) 661 and a DIAC or symmetrical trigger diode662. The voltage division circuit includes bipolar junction transistors(BJT) 667 and 668 and resistors 664, 665, 666, and 671.

Bidirectional triode thyristor 661 has a first terminal connected tofiltering output terminal 521, a second terminal connected to filteringoutput terminal 522, and a control terminal connected to a firstterminal of symmetrical trigger diode 662, which has a second terminalconnected to an end of capacitor 663, which has another end connected tofiltering output terminal 522. Resistor 664 is in parallel to capacitor663, and has an end connected to the second terminal of symmetricaltrigger diode 662 and another end connected to filtering output terminal522. Resistor 665 has an end connected to the second terminal ofsymmetrical trigger diode 662 and another end connected to the collectorterminal of BJT 667, whose emitter terminal is connected to filteringoutput terminal 522. Resistor 666 has an end connected to the secondterminal of symmetrical trigger diode 662 and another end connected tothe collector terminal of BJT 668 and the base terminal of BJT 667. Theemitter terminal of BJT 668 is connected to filtering output terminal522. Resistor 669 has an end connected to the base terminal of BJT 668and another end connected to an end of capacitor 670, which has anotherend connected to filtering output terminal 522. Resistor 671 has an endconnected to the second terminal of symmetrical trigger diode 662 andanother end connected to the cathode of diode 672, whose anode isconnected to filtering output terminal 521.

It's worth noting that according to some embodiments, the resistance ofresistor 665 should be smaller than that of resistor 666.

Next, an exemplary operation of protection circuit 660 in overcurrentprotection is described as follows.

The node connecting resistor 669 and capacitor 670 is to receive acurrent detection signal S531, which represents the magnitude of currentthrough the LED module. The other end of resistor 671 is a voltageterminal 521′. In this embodiment concerning overcurrent protection,voltage terminal 521′ may be coupled to a biasing voltage source, or beconnected through diode 672 to filtering output terminal 521, as shownin FIG. 56B, to take a filtered signal as a biasing voltage source. Ifvoltage terminal 521′ is coupled to an external biasing voltage source,diode 672 may be omitted, so it is depicted in a dotted line in FIG.56B. The combination of resistor 669 and capacitor 670 can work tofilter out high frequency components of the current detection signalS531, and then input the filtered current detection signal S531 to thebase terminal of BJT 668 for controlling current conduction and cutoffof BJT 668. The filtering function of resistor 669 and capacitor 670 canprevent misoperation of BJT 668 due to noises. In practical use,resistor 669 and capacitor 670 may be omitted, so they are each depictedin a dotted line in FIG. 56B. When they are omitted, current detectionsignal S531 is input directly to the base terminal of BJT 668.

When the LED lamp is operating normally and the current of the LEDmodule is within a normal range, BJT 668 is in a cutoff state, andresistor 66 works to pull up the base voltage of BJT 667, whichtherefore enters a conducting state. In this state, the electricpotential at the second terminal of symmetrical trigger diode 662 isdetermined based on the voltage at voltage terminal 521′ of the biasingvoltage source and voltage division ratios between resistor 671 andparallel-connected resistors 664 and 665. Since the resistance ofresistor 665 is relatively small, voltage share for resistor 665 issmaller and the electric potential at the second terminal of symmetricaltrigger diode 662 is therefore pulled down. Then, the electric potentialat the control terminal of bidirectional triode thyristor 661 is in turnpulled down by symmetrical trigger diode 662, causing bidirectionaltriode thyristor 661 to enter a cutoff state, which cutoff state makesprotection circuit 660 not being in a protection state.

When the current of the LED module exceeds an overcurrent value, thelevel of current detection signal S531 will increase significantly tocause BJT 668 to enter a conducting state and then pull down the basevoltage of BJT 667, which thereby enters a cutoff state. In this case,the electric potential at the second terminal of symmetrical triggerdiode 662 is determined based on the voltage at voltage terminal 521′ ofthe biasing voltage source and voltage division ratios between resistor671 and parallel-connected resistors 664 and 666. Since the resistanceof resistor 666 is relatively high, voltage share for resistor 666 islarger and the electric potential at the second terminal of symmetricaltrigger diode 662 is therefore higher. Then the electric potential atthe control terminal of bidirectional triode thyristor 661 is in turnpulled up by symmetrical trigger diode 662, causing bidirectional triodethyristor 661 to enter a conducting state, which conducting state worksto restrain or clamp down on the voltage between filtering outputterminals 521 and 522 and thus makes protection circuit 660 being in aprotection state.

In this embodiment, the voltage at voltage terminal 521′ of the biasingvoltage source is determined based on the trigger voltage ofbidirectional triode thyristor 661, and voltage division ratio betweenresistor 671 and parallel-connected resistors 664 and 665, or voltagedivision ratio between resistor 671 and parallel-connected resistors 664and 666. Through voltage division between resistor 671 andparallel-connected resistors 664 and 665, the voltage from voltageterminal 521′ at symmetrical trigger diode 662 will be lower than thetrigger voltage of bidirectional triode thyristor 661. Otherwise,through voltage division between resistor 671 and parallel-connectedresistors 664 and 666, the voltage from voltage terminal 521′ atsymmetrical trigger diode 662 will be higher than the trigger voltage ofbidirectional triode thyristor 661. For example, in some embodiments,when the current of the LED module exceeds an overcurrent value, thevoltage division circuit is adjusted to the voltage division ratiobetween resistor 671 and parallel-connected resistors 664 and 666,causing a higher portion of the voltage at voltage terminal 521′ toresult at symmetrical trigger diode 662, achieving a hysteresisfunction. Specifically, BJTs 667 and 668 as switches are respectivelyconnected in series to resistors 665 and 666 which determine the voltagedivision ratios. The voltage division circuit is configured to controlturning on which one of BJTs 667 and 668 and leaving the other off fordetermining the relevant voltage division ratio, according to whetherthe current of the LED module exceeds an overcurrent value. And theclamping circuit determines whether to restrain or clamp down on thevoltage of the LED module according to the applying voltage divisionratio.

Next, an exemplary operation of protection circuit 660 in overvoltageprotection is described as follows.

The node connecting resistor 669 and capacitor 670 is to receive acurrent detection signal S531, which represents the magnitude of currentthrough the LED module. As described above, protection circuit 660 stillworks to provide overcurrent protection. The other end of resistor 671is a voltage terminal 521′. In this embodiment concerning overvoltageprotection, voltage terminal 521′ is coupled to the positive terminal ofthe LED module to detect the voltage of the LED module. Takingpreviously described embodiments for example, in embodiments of FIGS.53A and 53B, LED driving module 530 doesn't include driving circuit1530, and the voltage terminal 521′ would be coupled to filtering outputterminal 521. Whereas in embodiments of FIGS. 54A˜54G, LED drivingmodule 530 includes driving circuit 1530, and the voltage terminal 521′would be coupled to driving output terminal 1521. In this embodiment,voltage division ratios between resistor 671 and parallel-connectedresistors 664 and 665, and voltage division ratios between resistor 671and parallel-connected resistors 664 and 666 will be adjusted accordingto the voltage at voltage terminal 521′, for example, the voltage atdriving output terminal 1521 or filtering output terminal 521.Therefore, normal overcurrent protection can still be provided byprotection circuit 660.

In some embodiments, when the LED lamp is operating normally, assumingovercurrent condition doesn't occur, the electric potential at thesecond terminal of symmetrical trigger diode 662 is determined based onthe voltage at voltage terminal 521′ and voltage division ratios betweenresistor 671 and parallel-connected resistors 664 and 665, and isinsufficient to trigger bidirectional triode thyristor 661. Thenbidirectional triode thyristor 661 is in a cutoff state, makingprotection circuit 660 not being in a protection state. On the otherhand, when the LED module is operating abnormally with the voltage atthe positive terminal of the LED module exceeding an overvoltage value,the electric potential at the second terminal of symmetrical triggerdiode 662 is sufficiently high to trigger bidirectional triode thyristor661 when the voltage at the first terminal of symmetrical trigger diode662 is larger than the trigger voltage of bidirectional triode thyristor661. Then bidirectional triode thyristor 661 enters a conducting state,making protection circuit 660 being in a protection state to restrain orclamp down on the level of the filtered signal.

As described above, protection circuit 660 provides one or two of thefunctions of overcurrent protection and overvoltage protection.

In some embodiments, protection circuit 660 may further include a zenerdiode connected to resistor 664 in parallel, which zener diode is usedto limit or restrain the voltage across resistor 664. The breakdownvoltage of the zener diode is in some embodiments in the range of about25˜50 volts, and is may preferably be about 36 volts.

Further, a silicon controlled rectifier may be substituted forbidirectional triode thyristor 661, without negatively affecting theprotection functions. Using a silicon controlled rectifier instead of abidirectional triode thyristor 661 has a lower voltage drop acrossitself in conduction than that across bidirectional triode thyristor 661in conduction.

In one embodiment, values of the parameters of protection circuit 660may be set as follows. Resistance of resistor 669 may be about 10 ohms.Capacitance of capacitor 670 may be about 1 nF. Capacitance of capacitor633 may be about 10 nF. The (breakover) voltage of symmetrical triggerdiode 662 may be in the range of about 26˜36 volts. Resistance ofresistor 671 may be in the range of about 300 k˜600 k ohms, and maypreferably be, in some embodiments, about 540 k ohms. Resistance ofresistor 666 is in some embodiments in the range of about 100 k˜300 kohms, and may preferably be, in some embodiments, about 220 k ohms.Resistance of resistor 665 is in some embodiments in the range of about30 k˜100 k ohms, and may preferably be, in some embodiments about 40 kohms. Resistance of resistor 664 is in some embodiments in the range ofabout 100 k˜300 k ohms, and may preferably be, in some embodiments about220 k ohms.

FIG. 57A is a block diagram of a power supply module in an LED lampaccording to an embodiment of the present invention. Compared to FIG.54A, the embodiment of FIG. 57A includes rectifying circuits 510 and540, a filtering circuit 520, and an LED driving module 530 including adriving circuit 1530 and an LED module 630, and further includes a modeswitching circuit 580. Mode switching circuit 580 is coupled to at leastone of filtering output terminals 521 and 522 and at least one ofdriving output terminals 1521 and 1522, for determining whether toperform a first driving mode or a second driving mode, as according to afrequency of the external driving signal. In the first driving mode, afiltered signal from filtering circuit 520 is input into driving circuit1530, while in the second driving mode the filtered signal bypasses atleast a component of driving circuit 1530, making driving circuit 1530stop working in conducting the filtered signal, allowing the filteredsignal to (directly) reach and drive LED module 630. The bypassedcomponent(s) of driving circuit 1530 may include an inductor or aswitch, which when bypassed makes driving circuit 1530 unable totransfer and/or convert power, and then stop working in conducting thefiltered signal. If driving circuit 1530 includes a capacitor, thecapacitor can still be used to filter out ripples of the filtered signalin order to stabilize the voltage across the LED module. When modeswitching circuit 580 determines on performing the first driving mode,allowing the filtered signal to be input to driving circuit 1530,driving circuit 1530 then transforms the filtered signal into a drivingsignal for driving LED module 630 to emit light. On the other hand, whenmode switching circuit 580 determines on performing the second drivingmode, allowing the filtered signal to bypass driving circuit 1530 toreach LED module 630, filtering circuit 520 becomes in effect a drivingcircuit for LED module 630. Then filtering circuit 520 provides thefiltered signal as a driving signal for the LED module for driving theLED module to emit light.

It's worth noting that mode switching circuit 580 can determine whetherto perform the first driving mode or the second driving mode based on auser's instruction or a detected signal received by the LED lamp throughpins 501, 502, 503, and 504. With the mode switching circuit, the powersupply module of the LED lamp can adapt to or perform one of appropriatedriving modes corresponding to different application environments ordriving systems, thus improving the compatibility of the LED lamp. Insome embodiments, rectifying circuit 540 may be omitted, and is thusdepicted in a dotted line in FIG. 57A.

FIG. 57B is a schematic diagram of the mode switching circuit in an LEDlamp according to an embodiment of the present invention. Referring toFIG. 57B, a mode switching circuit 680 includes a mode switch 681suitable for use with the driving circuit 1630 in FIG. 54C. Referring toFIGS. 57B and 54C, mode switch 681 has three terminals 683, 684, and685, wherein terminal 683 is coupled to driving output terminal 1522,terminal 684 is coupled to filtering output terminal 522, and terminal685 is coupled to the inductor 1632 in driving circuit 1630.

When mode switching circuit 680 determines on performing a first drivingmode, mode switch 681 conducts current in a first conductive paththrough terminals 683 and 685 and a second conductive path throughterminals 683 and 684 is in a cutoff state. In this case, driving outputterminal 1522 is coupled to inductor 1632, and therefore driving circuit1630 is working normally, which working includes receiving a filteredsignal from filtering output terminals 521 and 522 and then transformingthe filtered signal into a driving signal, output at driving outputterminals 1521 and 1522 for driving the LED module.

When mode switching circuit 680 determines on performing a seconddriving mode, mode switch 681 conducts current in the second conductivepath through terminals 683 and 684 and the first conductive path throughterminals 683 and 685 is in a cutoff state. In this case, driving outputterminal 1522 is coupled to filtering output terminal 522, and thereforedriving circuit 1630 stops working, and a filtered signal is inputthrough filtering output terminals 521 and 522 to driving outputterminals 1521 and 1522 for driving the LED module, while bypassinginductor 1632 and switch 1635 in driving circuit 1630.

FIG. 57C is a schematic diagram of the mode switching circuit in an LEDlamp according to an embodiment of the present invention. Referring toFIG. 57C, a mode switching circuit 780 includes a mode switch 781suitable for use with the driving circuit 1630 in FIG. 54C. Referring toFIGS. 57C and 54C, mode switch 781 has three terminals 783, 784, and785, wherein terminal 783 is coupled to filtering output terminal 522,terminal 784 is coupled to driving output terminal 1522, and terminal785 is coupled to switch 1635 in driving circuit 1630.

When mode switching circuit 780 determines on performing a first drivingmode, mode switch 781 conducts current in a first conductive paththrough terminals 783 and 785 and a second conductive path throughterminals 783 and 784 is in a cutoff state. In this case, filteringoutput terminal 522 is coupled to switch 1635, and therefore drivingcircuit 1630 is working normally, which working includes receiving afiltered signal from filtering output terminals 521 and 522 and thentransforming the filtered signal into a driving signal, output atdriving output terminals 1521 and 1522 for driving the LED module.

When mode switching circuit 780 determines on performing a seconddriving mode, mode switch 781 conducts current in the second conductivepath through terminals 783 and 784 and the first conductive path throughterminals 783 and 785 is in a cutoff state. In this case, driving outputterminal 1522 is coupled to filtering output terminal 522, and thereforedriving circuit 1630 stops working, and a filtered signal is inputthrough filtering output terminals 521 and 522 to driving outputterminals 1521 and 1522 for driving the LED module, while bypassinginductor 1632 and switch 1635 in driving circuit 1630.

FIG. 57D is a schematic diagram of the mode switching circuit in an LEDlamp according to an embodiment of the present invention. Referring toFIG. 57D, a mode switching circuit 880 includes a mode switch 881suitable for use with the driving circuit 1730 in FIG. 54D. Referring toFIGS. 57D and 54D, mode switch 881 has three terminals 883, 884, and885, wherein terminal 883 is coupled to filtering output terminal 521,terminal 884 is coupled to driving output terminal 1521, and terminal885 is coupled to inductor 1732 in driving circuit 1730.

When mode switching circuit 880 determines on performing a first drivingmode, mode switch 881 conducts current in a first conductive paththrough terminals 883 and 885 and a second conductive path throughterminals 883 and 884 is in a cutoff state. In this case, filteringoutput terminal 521 is coupled to inductor 1732, and therefore drivingcircuit 1730 is working normally, which working includes receiving afiltered signal from filtering output terminals 521 and 522 and thentransforming the filtered signal into a driving signal, output atdriving output terminals 1521 and 1522 for driving the LED module.

When mode switching circuit 880 determines on performing a seconddriving mode, mode switch 881 conducts current in the second conductivepath through terminals 883 and 884 and the first conductive path throughterminals 883 and 885 is in a cutoff state. In this case, driving outputterminal 1521 is coupled to filtering output terminal 521, and thereforedriving circuit 1730 stops working, and a filtered signal is inputthrough filtering output terminals 521 and 522 to driving outputterminals 1521 and 1522 for driving the LED module, while bypassinginductor 1732 and freewheeling diode 1733 in driving circuit 1730.

FIG. 57E is a schematic diagram of the mode switching circuit in an LEDlamp according to an embodiment of the present invention. Referring toFIG. 57E, a mode switching circuit 980 includes a mode switch 981suitable for use with the driving circuit 1730 in FIG. 54D. Referring toFIGS. 57E and 54D, mode switch 981 has three terminals 983, 984, and985, wherein terminal 983 is coupled to driving output terminal 1521,terminal 984 is coupled to filtering output terminal 521, and terminal985 is coupled to the cathode of diode 1733 in driving circuit 1730.

When mode switching circuit 980 determines on performing a first drivingmode, mode switch 981 conducts current in a first conductive paththrough terminals 983 and 985 and a second conductive path throughterminals 983 and 984 is in a cutoff state. In this case, filteringoutput terminal 521 is coupled to the cathode of diode 1733, andtherefore driving circuit 1730 is working normally, which workingincludes receiving a filtered signal from filtering output terminals 521and 522 and then transforming the filtered signal into a driving signal,output at driving output terminals 1521 and 1522 for driving the LEDmodule.

When mode switching circuit 980 determines on performing a seconddriving mode, mode switch 981 conducts current in the second conductivepath through terminals 983 and 984 and the first conductive path throughterminals 983 and 985 is in a cutoff state. In this case, driving outputterminal 1521 is coupled to filtering output terminal 521, and thereforedriving circuit 1730 stops working, and a filtered signal is inputthrough filtering output terminals 521 and 522 to driving outputterminals 1521 and 1522 for driving the LED module, while bypassinginductor 1732 and freewheeling diode 1733 in driving circuit 1730.

FIG. 57F is a schematic diagram of the mode switching circuit in an LEDlamp according to an embodiment of the present invention. Referring toFIG. 57F, a mode switching circuit 1680 includes a mode switch 1681suitable for use with the driving circuit 1830 in FIG. 54E. Referring toFIGS. 57F and 54E, mode switch 1681 has three terminals 1683, 1684, and1685, wherein terminal 1683 is coupled to filtering output terminal 521,terminal 1684 is coupled to driving output terminal 1521, and terminal1685 is coupled to switch 1835 in driving circuit 1830.

When mode switching circuit 1680 determines on performing a firstdriving mode, mode switch 1681 conducts current in a first conductivepath through terminals 1683 and 1685 and a second conductive paththrough terminals 1683 and 1684 is in a cutoff state. In this case,filtering output terminal 521 is coupled to switch 1835, and thereforedriving circuit 1830 is working normally, which working includesreceiving a filtered signal from filtering output terminals 521 and 522and then transforming the filtered signal into a driving signal, outputat driving output terminals 1521 and 1522 for driving the LED module.

When mode switching circuit 1680 determines on performing a seconddriving mode, mode switch 1681 conducts current in the second conductivepath through terminals 1683 and 1684 and the first conductive paththrough terminals 1683 and 1685 is in a cutoff state. In this case,driving output terminal 1521 is coupled to filtering output terminal521, and therefore driving circuit 1830 stops working, and a filteredsignal is input through filtering output terminals 521 and 522 todriving output terminals 1521 and 1522 for driving the LED module, whilebypassing inductor 1832 and switch 1835 in driving circuit 1830.

FIG. 57G is a schematic diagram of the mode switching circuit in an LEDlamp according to an embodiment of the present invention. Referring toFIG. 57G, a mode switching circuit 1780 includes a mode switch 1781suitable for use with the driving circuit 1830 in FIG. 54E. Referring toFIGS. 57G and 54E, mode switch 1781 has three terminals 1783, 1784, and1785, wherein terminal 1783 is coupled to filtering output terminal 521,terminal 1784 is coupled to driving output terminal 1521, and terminal1785 is coupled to inductor 1832 in driving circuit 1830.

When mode switching circuit 1780 determines on performing a firstdriving mode, mode switch 1781 conducts current in a first conductivepath through terminals 1783 and 1785 and a second conductive paththrough terminals 1783 and 1784 is in a cutoff state. In this case,filtering output terminal 521 is coupled to inductor 1832, and thereforedriving circuit 1830 is working normally, which working includesreceiving a filtered signal from filtering output terminals 521 and 522and then transforming the filtered signal into a driving signal, outputat driving output terminals 1521 and 1522 for driving the LED module.

When mode switching circuit 1780 determines on performing a seconddriving mode, mode switch 1781 conducts current in the second conductivepath through terminals 1783 and 1784 and the first conductive paththrough terminals 1783 and 1785 is in a cutoff state. In this case,driving output terminal 1521 is coupled to filtering output terminal521, and therefore driving circuit 1830 stops working, and a filteredsignal is input through filtering output terminals 521 and 522 todriving output terminals 1521 and 1522 for driving the LED module, whilebypassing inductor 1832 and switch 1835 in driving circuit 1830.

FIG. 57H is a schematic diagram of the mode switching circuit in an LEDlamp according to an embodiment of the present invention. Referring toFIG. 57H, a mode switching circuit 1880 includes mode switches 1881 and1882 suitable for use with the driving circuit 1930 in FIG. 54F.Referring to FIGS. 57H and 54F, mode switch 1881 has three terminals1883, 1884, and 1885, wherein terminal 1883 is coupled to driving outputterminal 1521, terminal 1884 is coupled to filtering output terminal521, and terminal 1885 is coupled to freewheeling diode 1933 in drivingcircuit 1930. And mode switch 1882 has three terminals 1886, 1887, and1888, wherein terminal 1886 is coupled to driving output terminal 1522,terminal 1887 is coupled to filtering output terminal 522, and terminal1888 is coupled to filtering output terminal 521.

When mode switching circuit 1880 determines on performing a firstdriving mode, mode switch 1881 conducts current in a first conductivepath through terminals 1883 and 1885 and a second conductive paththrough terminals 1883 and 1884 is in a cutoff state, and mode switch1882 conducts current in a third conductive path through terminals 1886and 1888 and a fourth conductive path through terminals 1886 and 1887 isin a cutoff state. In this case, driving output terminal 1521 is coupledto freewheeling diode 1933, and filtering output terminal 521 is coupledto driving output terminal 1522. Therefore driving circuit 1930 isworking normally, which working includes receiving a filtered signalfrom filtering output terminals 521 and 522 and then transforming thefiltered signal into a driving signal, output at driving outputterminals 1521 and 1522 for driving the LED module.

When mode switching circuit 1880 determines on performing a seconddriving mode, mode switch 1881 conducts current in the second conductivepath through terminals 1883 and 1884 and the first conductive paththrough terminals 1883 and 1885 is in a cutoff state, and mode switch1882 conducts current in the fourth conductive path through terminals1886 and 1887 and the third conductive path through terminals 1886 and1888 is in a cutoff state. In this case, driving output terminal 1521 iscoupled to filtering output terminal 521, and filtering output terminal522 is coupled to driving output terminal 1522. Therefore drivingcircuit 1930 stops working, and a filtered signal is input throughfiltering output terminals 521 and 522 to driving output terminals 1521and 1522 for driving the LED module, while bypassing freewheeling diode1933 and switch 1935 in driving circuit 1930.

FIG. 57I is a schematic diagram of the mode switching circuit in an LEDlamp according to an embodiment of the present invention. Referring toFIG. 57I, a mode switching circuit 1980 includes mode switches 1981 and1982 suitable for use with the driving circuit 1930 in FIG. 54F.Referring to FIGS. 57I and 54F, mode switch 1981 has three terminals1983, 1984, and 1985, wherein terminal 1983 is coupled to filteringoutput terminal 522, terminal 1984 is coupled to driving output terminal1522, and terminal 1985 is coupled to switch 1935 in driving circuit1930. And mode switch 1982 has three terminals 1986, 1987, and 1988,wherein terminal 1986 is coupled to filtering output terminal 521,terminal 1987 is coupled to driving output terminal 1521, and terminal1988 is coupled to driving output terminal 1522.

When mode switching circuit 1980 determines on performing a firstdriving mode, mode switch 1981 conducts current in a first conductivepath through terminals 1983 and 1985 and a second conductive paththrough terminals 1983 and 1984 is in a cutoff state, and mode switch1982 conducts current in a third conductive path through terminals 1986and 1988 and a fourth conductive path through terminals 1986 and 1987 isin a cutoff state. In this case, driving output terminal 1522 is coupledto filtering output terminal 521, and filtering output terminal 522 iscoupled to switch 1935. Therefore driving circuit 1930 is workingnormally, which working includes receiving a filtered signal fromfiltering output terminals 521 and 522 and then transforming thefiltered signal into a driving signal, output at driving outputterminals 1521 and 1522 for driving the LED module.

When mode switching circuit 1980 determines on performing a seconddriving mode, mode switch 1981 conducts current in the second conductivepath through terminals 1983 and 1984 and the first conductive paththrough terminals 1983 and 1985 is in a cutoff state, and mode switch1982 conducts current in the fourth conductive path through terminals1986 and 1987 and the third conductive path through terminals 1986 and1988 is in a cutoff state. In this case, driving output terminal 1521 iscoupled to filtering output terminal 521, and filtering output terminal522 is coupled to driving output terminal 1522. Therefore drivingcircuit 1930 stops working, and a filtered signal is input throughfiltering output terminals 521 and 522 to driving output terminals 1521and 1522 for driving the LED module, while bypassing freewheeling diode1933 and switch 1935 in driving circuit 1930.

It's worth noting that the mode switches in the above embodiments mayeach comprise, for example, a single-pole double-throw switch, orcomprise two semiconductor switches (such as metal oxide semiconductortransistors), for switching a conductive path on to conduct currentwhile leaving the other conductive path cutoff. Each of the twoconductive paths provides a path for conducting the filtered signal,allowing the current of the filtered signal to flow through one of thetwo paths, thereby achieving the function of mode switching orselection. For example, with reference to FIGS. 49A, 49B, and 49D inaddition, when the lamp driving circuit 505 is not present and the LEDtube lamp 500 is directly supplied by the AC power supply 508, the modeswitching circuit may determine on performing a first driving mode inwhich the driving circuit (such as driving circuit 1530, 1630, 1730,1830, or 1930) transforms the filtered signal into a driving signal of alevel meeting a required level to properly drive the LED module to emitlight. On the other hand, when the lamp driving circuit 505 is present,the mode switching circuit may determine on performing a second drivingmode in which the filtered signal is (almost) directly used to drive theLED module to emit light; or alternatively the mode switching circuitmay determine on performing the first driving mode to drive the LEDmodule to emit light.

FIG. 58A is a block diagram of a power supply module in an LED lampaccording to an embodiment of the present invention. Compared to FIG.49E, the embodiment of FIG. 58A includes rectifying circuits 510 and540, a filtering circuit 520, and an LED driving module 530, and furtherincludes a ballast-compatible circuit 1510. The ballast-compatiblecircuit 1510 may be coupled between pin 501 and/or pin 502 andrectifying circuit 510. This embodiment is explained assuming theballast-compatible circuit 1510 to be coupled between pin 501 andrectifying circuit 510. With reference to FIGS. 49A, 49B, and 49D inaddition to FIG. 58A, lamp driving circuit 505 comprises a ballastconfigured to provide an AC driving signal to drive the LED lamp in thisembodiment.

In an initial stage upon the activation of the driving system of lampdriving circuit 505, lamp driving circuit 505's ability to outputrelevant signal(s) has not risen to a standard state. However, in theinitial stage the power supply module of the LED lamp instantly orrapidly receives or conducts the AC driving signal provided by lampdriving circuit 505, which initial conduction is likely to fail thestarting of the LED lamp by lamp driving circuit 505 as lamp drivingcircuit 505 is initially loaded by the LED lamp in this stage. Forexample, internal components of lamp driving circuit 505 may need toretrieve power from a transformed output in lamp driving circuit 505, inorder to maintain their operation upon the activation. In this case, theactivation of lamp driving circuit 505 may end up failing as its outputvoltage could not normally rise to a required level in this initialstage; or the quality factor (Q) of a resonant circuit in lamp drivingcircuit 505 may vary as a result of the initial loading from the LEDlamp, so as to cause the failure of the activation.

In this embodiment, in the initial stage upon activation,ballast-compatible circuit 1510 will be in an open-circuit state,preventing the energy of the AC driving signal from reaching the LEDmodule. After a defined delay upon the AC driving signal as an externaldriving signal being input to the LED tube lamp, ballast-compatiblecircuit 1510 switches from a cutoff state during the delay to aconducting state, allowing the energy of the AC driving signal to startto reach the LED module. By means of the delayed conduction ofballast-compatible circuit 1510, operation of the LED lamp simulates thelamp-starting characteristics of a fluorescent lamp, that is, internalgases of the fluorescent lamp will normally discharge for light emissionafter a delay upon activation of a driving power supply. Therefore,ballast-compatible circuit 1510 further improves the compatibility ofthe LED lamp with lamp driving circuits 505 such as an electronicballast.

In this embodiment, rectifying circuit 540 may be omitted and istherefore depicted by a dotted line in FIG. 58A.

FIG. 58B is a block diagram of a power supply module in an LED lampaccording to an embodiment of the present invention. Compared to FIG.58A, ballast-compatible circuit 1510 in the embodiment of FIG. 58B iscoupled between pin 503 and/or pin 504 and rectifying circuit 540. Asexplained regarding ballast-compatible circuit 1510 in FIG. 58A,ballast-compatible circuit 1510 in FIG. 58B performs the function ofdelaying the starting of the LED lamp, or causing the input of the ACdriving signal to be delayed for a predefined time, in order to preventthe failure of starting by lamp driving circuits 505 such as anelectronic ballast.

Apart from coupling ballast-compatible circuit 1510 between terminalpin(s) and rectifying circuit in the above embodiments,ballast-compatible circuit 1510 may alternatively be included within arectifying circuit with a different structure. FIG. 58C illustrates anarrangement with a ballast-compatible circuit in an LED lamp accordingto a preferred embodiment of the present invention. Referring to FIG.58C, the rectifying circuit assumes the circuit structure of rectifyingcircuit 810 in FIG. 50C. Rectifying circuit 810 includes rectifying unit815 and terminal adapter circuit 541. Rectifying unit 815 is coupled topins 501 and 502, terminal adapter circuit 541 is coupled to filteringoutput terminals 511 and 512, and the ballast-compatible circuit 1510 inFIG. 58C is coupled between rectifying unit 815 and terminal adaptercircuit 541. In this case, in the initial stage upon activation of theballast, an AC driving signal as an external driving signal is input tothe LED tube lamp, where the AC driving signal can only reach rectifyingunit 815, but cannot reach other circuits such as terminal adaptercircuit 541, other internal filter circuitry, and the LED drivingmodule. Moreover, parasitic capacitors associated with rectifying diodes811 and 812 within rectifying unit 815 are quite small in capacitanceand thus can be ignored. Accordingly, lamp driving circuit 505 in theinitial stage isn't loaded with or effectively connected to theequivalent capacitor or inductor of the power supply module of the LEDlamp, and the quality factor (Q) of lamp driving circuit 505 istherefore not adversely affected in this stage, resulting in asuccessful starting of the LED lamp by lamp driving circuit 505.

It's worth noting that under the condition that terminal adapter circuit541 doesn't include components such as capacitors or inductors,interchanging rectifying unit 815 and terminal adapter circuit 541 inposition, meaning rectifying unit 815 is connected to filtering outputterminals 511 and 512 and terminal adapter circuit 541 is connected topins 501 and 502, doesn't affect or alter the function ofballast-compatible circuit 1510.

Further, as explained in FIGS. 50A˜50D, when a rectifying circuit isconnected to pins 503 and 504 instead of pins 501 and 502, thisrectifying circuit may constitute the rectifying circuit 540. That is,the circuit arrangement with a ballast-compatible circuit 1510 in FIG.58C may be alternatively included in rectifying circuit 540 instead ofrectifying circuit 810, without affecting the function ofballast-compatible circuit 1510.

In some embodiments, as described above terminal adapter circuit 541doesn't include components such as capacitors or inductors. Or whenrectifying circuit 610 in FIG. 50A constitutes the rectifying circuit510 or 540, parasitic capacitances in the rectifying circuit 510 or 540are quite small and thus can be ignored. These conditions contribute tonot affecting the quality factor of lamp driving circuit 505.

FIG. 58D is a block diagram of a power supply module in an LED lampaccording to an embodiment of the present invention. Compared to theembodiment of FIG. 58A, ballast-compatible circuit 1510 in theembodiment of FIG. 58D is coupled between rectifying circuit 540 andfiltering circuit 520. Since rectifying circuit 540 also doesn't includecomponents such as capacitors or inductors, the function ofballast-compatible circuit 1510 in the embodiment of FIG. 58D will notbe affected.

FIG. 58E is a block diagram of a power supply module in an LED lampaccording to an embodiment of the present invention. Compared to theembodiment of FIG. 58A, ballast-compatible circuit 1510 in theembodiment of FIG. 58E is coupled between rectifying circuit 510 andfiltering circuit 520. Similarly, since rectifying circuit 510 doesn'tinclude components such as capacitors or inductors, the function ofballast-compatible circuit 1510 in the embodiment of FIG. 58E will notbe affected.

FIG. 58F is a schematic diagram of the ballast-compatible circuitaccording to an embodiment of the present invention. Referring to FIG.58F, a ballast-compatible circuit 1610 has an initial state in which anequivalent open-circuit is obtained at ballast-compatible circuit inputand output terminals 1611 and 1621. Upon receiving an input signal atballast-compatible circuit input terminal 1611, a delay will pass untila current conduction occurs through and between ballast-compatiblecircuit input and output terminals 1611 and 1621, transmitting the inputsignal to ballast-compatible circuit output terminal 1621.

Ballast-compatible circuit 1610 includes a diode 1612, resistors 1613,1615, 1618, 1620, and 1622, a bidirectional triode thyristor (TRIAC)1614, a DIAC or symmetrical trigger diode 1617, a capacitor 1619, andballast-compatible circuit input and output terminals 1611 and 1621.It's noted that the resistance of resistor 1613 should be quite large sothat when bidirectional triode thyristor 1614 is cutoff in anopen-circuit state, an equivalent open-circuit is obtained atballast-compatible circuit input and output terminals 1611 and 1621.

Bidirectional triode thyristor 1614 is coupled betweenballast-compatible circuit input and output terminals 1611 and 1621, andresistor 1613 is also coupled between ballast-compatible circuit inputand output terminals 1611 and 1621 and in parallel to bidirectionaltriode thyristor 1614. Diode 1612, resistors 1620 and 1622, andcapacitor 1619 are series-connected in sequence betweenballast-compatible circuit input and output terminals 1611 and 1621, andare connected in parallel to bidirectional triode thyristor 1614. Diode1612 has an anode connected to bidirectional triode thyristor 1614, andhas a cathode connected to an end of resistor 1620. Bidirectional triodethyristor 1614 has a control terminal connected to a terminal ofsymmetrical trigger diode 1617, which has another terminal connected toan end of resistor 1618, which has another end connected to a nodeconnecting capacitor 1619 and resistor 1622. Resistor 1615 is connectedbetween the control terminal of bidirectional triode thyristor 1614 anda node connecting resistor 1613 and capacitor 1619.

When an AC driving signal (such as a high-frequency high-voltage ACsignal output by an electronic ballast) is initially input toballast-compatible circuit input terminal 1611, bidirectional triodethyristor 1614 will be in an open-circuit state, not allowing the ACdriving signal to pass through and the LED lamp is therefore also in anopen-circuit state. In this state, the AC driving signal is chargingcapacitor 1619 through diode 1612 and resistors 1620 and 1622, graduallyincreasing the voltage of capacitor 1619. Upon continually charging fora period of time, the voltage of capacitor 1619 increases to be abovethe trigger voltage value of symmetrical trigger diode 1617 so thatsymmetrical trigger diode 1617 is turned on in a conducting state. Thenthe conducting symmetrical trigger diode 1617 will in turn triggerbidirectional triode thyristor 1614 on in a conducting state. In thissituation, the conducting bidirectional triode thyristor 1614electrically connects ballast-compatible circuit input and outputterminals 1611 and 1621, allowing the AC driving signal to flow throughballast-compatible circuit input and output terminals 1611 and 1621,thus starting the operation of the power supply module of the LED lamp.In this case the energy stored by capacitor 1619 will maintain theconducting state of bidirectional triode thyristor 1614, to prevent theAC variation of the AC driving signal from causing bidirectional triodethyristor 1614 and therefore ballast-compatible circuit 1610 to becutoff again, or to prevent the problem of bidirectional triodethyristor 1614 alternating or switching between its conducting andcutoff states.

In general, in hundreds of milliseconds upon activation of a lampdriving circuit 505 such as an electronic ballast, the output voltage ofthe ballast has risen above a certain voltage value as the outputvoltage hasn't been adversely affected by the sudden initial loadingfrom the LED lamp. A detection mechanism to detect whether lighting of afluorescent lamp is achieved may be disposed in lamp driving circuits505 such as an electronic ballast. In this detection mechanism, if afluorescent lamp fails to be lit up for a defined period of time, anabnormal state of the fluorescent lamp is detected, causing thefluorescent lamp to enter a protection state. In view of these facts, incertain embodiments, the delay provided by ballast-compatible circuit1610 until conduction of ballast-compatible circuit 1610 and then theLED lamp should be and may preferably be in the range of about 0.1˜3seconds.

It's worth noting that an additional capacitor 1623 may be coupled inparallel to resistor 1622. Capacitor 1623 works to reflect or supportinstantaneous change in the voltage between ballast-compatible circuitinput and output terminals 1611 and 1621, and will not affect thefunction of delayed conduction performed by ballast-compatible circuit1610.

FIG. 58G is a block diagram of a power supply module in an LED lampaccording to an embodiment of the present invention. Compared to theembodiment of FIG. 49D, lamp driving circuit 505 in the embodiment ofFIG. 58G drives a plurality of LED tube lamps 500 connected in series,wherein a ballast-compatible circuit 1610 is disposed in each of the LEDtube lamps 500. For the convenience of illustration, twoseries-connected LED tube lamps 500 are assumed for example andexplained as follows.

Because the two ballast-compatible circuits 1610 respectively of the twoLED tube lamps 500 can actually have different delays until conductionof the LED tube lamps 500, due to various factors such as errorsoccurring in production processes of some components, the actual timingof conduction of each of the ballast-compatible circuits 1610 isdifferent. Upon activation of a lamp driving circuit 505, the voltage ofthe AC driving signal provided by lamp driving circuit 505 will beshared out by the two LED tube lamps 500 roughly equally. Subsequentlywhen only one of the two LED tube lamps 500 first enters a conductingstate, the voltage of the AC driving signal then will be borne mostly orentirely by the other LED tube lamp 500. This situation will cause thevoltage across the ballast-compatible circuits 1610 in the other LEDtube lamp 500 that's not conducting to suddenly increase or be doubled,meaning the voltage between ballast-compatible circuit input and outputterminals 1611 and 1621 might even be suddenly doubled. In view of this,if capacitor 1623 is included, the voltage division effect betweencapacitors 1619 and 1623 will instantaneously increase the voltage ofcapacitor 1619, making symmetrical trigger diode 1617 triggeringbidirectional triode thyristor 1614 into a conducting state, thuscausing the two ballast-compatible circuits 1610 respectively of the twoLED tube lamps 500 to become conducting almost at the same time.Therefore, by introducing capacitor 1623, the situation, where one ofthe two ballast-compatible circuits 1610 respectively of the twoseries-connected LED tube lamps 500 that is first conducting has itsbidirectional triode thyristor 1614 then suddenly cutoff as havinginsufficient current passing through due to the discrepancy between thedelays provided by the two ballast-compatible circuits 1610 until theirrespective conductions, can be avoided. Therefore, using eachballast-compatible circuit 1610 with capacitor 1623 further improves thecompatibility of the series-connected LED tube lamps with each of lampdriving circuits 505 such as an electronic ballast.

In practical use, a suggested range of the capacitance of capacitor 1623is about 10 pF to about 1 nF, which may preferably be in the range ofabout 10 pF to about 100 pF, and may be even more desirable at about 47pF.

It's worth noting that diode 1612 is used or configured to rectify thesignal for charging capacitor 1619. Therefore, with reference to FIGS.58C, 58D, and 58E, in the case when ballast-compatible circuit 1610 isarranged following a rectifying unit or circuit, diode 1612 may beomitted. Thus diode 1612 is depicted in a dotted line in FIG. 58F.

FIG. 58H is a schematic diagram of the ballast-compatible circuitaccording to another embodiment of the present invention. Referring toFIG. 58H, a ballast-compatible circuit 1710 has an initial state inwhich an equivalent open-circuit is obtained at ballast-compatiblecircuit input and output terminals 1711 and 1721. Upon receiving aninput signal at ballast-compatible circuit input terminal 1711,ballast-compatible circuit 1710 will be in a cutoff state when the levelof the input external driving signal is below a defined valuecorresponding to a conduction delay of ballast-compatible circuit 1710;and ballast-compatible circuit 1710 will enter a conducting state uponthe level of the input external driving signal reaching the definedvalue, thus transmitting the input signal to ballast-compatible circuitoutput terminal 1721.

Ballast-compatible circuit 1710 includes a bidirectional triodethyristor (TRIAC) 1712, a DIAC or symmetrical trigger diode 1713,resistors 1714, 1716, and 1717, and a capacitor 1715. Bidirectionaltriode thyristor 1712 has a first terminal connected toballast-compatible circuit input terminal 1711; a control terminalconnected to a terminal of symmetrical trigger diode 1713 and an end ofresistor 1714; and a second terminal connected to another end ofresistor 1714. Capacitor 1715 has an end connected to another terminalof symmetrical trigger diode 1713, and has another end connected to thesecond terminal of bidirectional triode thyristor 1712. Resistor 1717 isin parallel connection with capacitor 1715, and is therefore alsoconnected to said another terminal of symmetrical trigger diode 1713 andthe second terminal of bidirectional triode thyristor 1712. And resistor1716 has an end connected to the node connecting capacitor 1715 andsymmetrical trigger diode 1713, and has another end connected toballast-compatible circuit output terminal 1721.

When an AC driving signal (such as a high-frequency high-voltage ACsignal output by an electronic ballast) is initially input toballast-compatible circuit input terminal 1711, bidirectional triodethyristor 1712 will be in an open-circuit state, not allowing the ACdriving signal to pass through and the LED lamp is therefore also in anopen-circuit state. The input of the AC driving signal causes apotential difference between ballast-compatible circuit input terminal1711 and ballast-compatible circuit output terminal 1721. When the ACdriving signal increases with time to eventually reach a sufficientamplitude (which is a defined level after the delay) after a period oftime, the signal level at ballast-compatible circuit output terminal1721 has a reflected voltage at the control terminal of bidirectionaltriode thyristor 1712 after passing through resistor 1716,parallel-connected capacitor 1715 and resistor 1717, and resistor 1714,wherein the reflected voltage then triggers bidirectional triodethyristor 1712 into a conducting state. This conducting state makesballast-compatible circuit 1710 entering a conducting state which causesthe LED lamp to operate normally. Upon bidirectional triode thyristor1712 conducting, a current flows through resistor 1716 and then chargescapacitor 1715 to store a specific voltage on capacitor 1715. In thiscase, the energy stored by capacitor 1715 will maintain the conductingstate of bidirectional triode thyristor 1712, to prevent the ACvariation of the AC driving signal from causing bidirectional triodethyristor 1712 and therefore ballast-compatible circuit 1710 to becutoff again, or to prevent the situation of bidirectional triodethyristor 1712 alternating or switching between its conducting andcutoff states.

FIG. 58I illustrates the ballast-compatible circuit according to anembodiment of the present invention. Referring to FIG. 58I, aballast-compatible circuit 1810 includes a housing 1812, a metallicelectrode 1813, a bimetallic strip 1814, and a heating filament 1816.Metallic electrode 1813 and heating filament 1816 protrude from thehousing 1812, so that they each have a portion inside the housing 1812and a portion outside of the housing 1812. Metallic electrode 1813'soutside portion has a ballast-compatible circuit input terminal 1811,and heating filament 1816's outside portion has a ballast-compatiblecircuit output terminal 1821. Housing 1812 is hermetic or tightly sealedand contains inertial gas 1815 such as helium gas. Bimetallic strip 1814is inside housing 1812 and is physically and electrically connected tothe portion of heating filament 1816 that is inside the housing 1812.And there is a spacing between bimetallic strip 1814 and metallicelectrode 1813, so that ballast-compatible circuit input terminal 1811and ballast-compatible circuit output terminal 1821 are not electricallyconnected in the initial state of ballast-compatible circuit 1810.Bimetallic strip 1814 may include two metallic strips with differenttemperature coefficients, wherein the metallic strip closer to metallicelectrode 1813 has a smaller temperature coefficient, and the metallicstrip more away from metallic electrode 1813 has a larger temperaturecoefficient.

When an AC driving signal (such as a high-frequency high-voltage ACsignal output by an electronic ballast) is initially input atballast-compatible circuit input terminal 1811 and ballast-compatiblecircuit output terminal 1821, a potential difference between metallicelectrode 1813 and heating filament 1816 is formed. When the potentialdifference increases enough to cause electric arc or arc dischargethrough inertial gas 1815, meaning when the AC driving signal increaseswith time to eventually reach the defined level after a delay, theninertial gas 1815 is then heated to cause bimetallic strip 1814 to swelltoward metallic electrode 1813 (as in the direction of the broken-linearrow in FIG. 58I), with this swelling eventually causing bimetallicstrip 1814 to bear against metallic electrode 1813, forming the physicaland electrical connections between them. In this situation, there iselectrical conduction between ballast-compatible circuit input terminal1811 and ballast-compatible circuit output terminal 1821. Then the ACdriving signal flows through and thus heats heating filament 1816. Inthis heating process, heating filament 1816 allows a current to flowthrough when electrical conduction exists between metallic electrode1813 and bimetallic strip 1814, causing the temperature of bimetallicstrip 1814 to be above a defined conduction temperature. As a result,since the respective temperature of the two metallic strips ofbimetallic strip 1814 with different temperature coefficients aremaintained above the defined conduction temperature, bimetallic strip1814 will bend against or toward metallic electrode 1813, thusmaintaining or supporting the physical joining or connection betweenbimetallic strip 1814 and metallic electrode 1813.

Therefore, upon receiving an input signal at ballast-compatible circuitinput and output terminals 1811 and 1821, a delay will pass until anelectrical/current conduction occurs through and betweenballast-compatible circuit input and output terminals 1811 and 1821.

Therefore, an exemplary ballast-compatible circuit such as describedherein may be coupled between any pin and any rectifying circuitdescribed above in the invention, wherein the ballast-compatible circuitwill be in a cutoff state in a defined delay upon an external drivingsignal being input to the LED tube lamp, and will enter a conductingstate after the delay. Otherwise, the ballast-compatible circuit will bein a cutoff state when the level of the input external driving signal isbelow a defined value corresponding to a conduction delay of theballast-compatible circuit; and ballast-compatible circuit will enter aconducting state upon the level of the input external driving signalreaching the defined value. Accordingly, the compatibility of the LEDtube lamp described herein with lamp driving circuits 505 such as anelectronic ballast is further improved by using such aballast-compatible circuit.

FIG. 59A is a block diagram of a power supply module in an LED tube lampaccording to an embodiment of the present invention. Compared to thatshown in FIG. 49E, the present embodiment comprises the rectifyingcircuits 510 and 540, the filtering circuit 520, and the LED drivingmodule 530, and further comprises two ballast-compatible circuits 1540.The two ballast-compatible circuits 1540 are coupled respectivelybetween the pin 503 and the rectifying output terminal 511 and betweenthe pin 504 and the rectifying output terminal 511. Referring to FIG.49A, FIG. 49B and FIG. 49D, the lamp driving circuit 505 is anelectronic ballast for supplying an AC driving signal to drive the LEDlamp of the present invention.

Two ballast-compatible circuits 1540 are initially in conducting states,and then enter into cutoff states in a delay. Therefore, in an initialstage upon activation of the lamp driving circuit 505, the AC drivingsignal is transmitted through the pin 503, the correspondingballast-compatible circuit 1540, the rectifying output terminal 511 andthe rectifying circuit 510, or through the pin 504, the correspondingballast-compatible circuit 1540, the rectifying output terminal 511 andthe rectifying circuit 510 of the LED lamp, and the filtering circuit520 and LED driving module 530 of the LED lamp are bypassed. Thereby,the LED lamp presents almost no load and does not affect the qualityfactor of the lamp driving circuit 505 at the beginning, and so the lampdriving circuit can be activated successfully. The twoballast-compatible circuits 1540 are cut off after a time period whilethe lamp driving circuit 505 has been activated successfully. Afterthat, the lamp driving circuit 505 has a sufficient drive capability fordriving the LED lamp to emit light.

FIG. 59B is a block diagram of a power supply module in an LED tube lampaccording to an embodiment of the present invention. Compared to thatshown in FIG. 59A, the two ballast-compatible circuits 1540 are changedto be coupled respectively between the pin 503 and the rectifying outputterminal 512 and between the pin 504 and the rectifying output terminal512. Similarly, two ballast-compatible circuits 1540 are initially inconducting states, and then changed to cutoff states after an objectivedelay. Thereby, the lamp driving circuit 505 drives the LED lamp to emitlight after the lamp driving circuit 505 has activated.

It is worth noting that the arrangement of the two ballast-compatiblecircuits 1540 may be changed to be coupled between the pin 501 and therectifying terminal 511 and between the pin 501 and the rectifyingterminal 511, or between the pin 501 and the rectifying terminal 512 andbetween the pin 501 and the rectifying terminal 512, for having the lampdriving circuit 505 drive the LED lamp to emit light after beingactivated.

FIG. 59C is a block diagram of a power supply module in an LED tube lampaccording to an embodiment of the present invention. Compared to thatshown in FIGS. 59A and 59B, the rectifying circuit 810 shown in FIG. 50Creplaces the rectifying circuit 540, and the rectifying unit 815 of therectifying circuit 810 is coupled to the pins 503 and 504 and theterminal adapter circuit 541 thereof is coupled to the rectifying outputterminals 511 and 512. The arrangement of the two ballast-compatiblecircuits 1540 is also changed to be coupled respectively between the pin501 and the half-wave node 819 and between the pin 502 and the half-wavenode 819.

In an initial stage upon activation of the lamp driving circuit 505, twoballast-compatible circuits 1540 are initially in conducting states. Atthis moment, the AC driving signal is transmitted through the pin 501,the corresponding ballast-compatible circuit 1540, the half-wave node819 and the rectifying unit 815 or the pin 502, the correspondingballast-compatible circuit 1540, the half-wave node 819 and therectifying unit 815 of the LED lamp, and the terminal adapter circuit541, the filtering circuit 520 and LED driving module 530 of the LEDlamp are bypassed. Thereby, the LED lamp presents almost no load anddoes not affect the quality factor of the lamp driving circuit 505 atthe beginning, and so the lamp driving circuit can be activatedsuccessfully. The two ballast-compatible circuits 1540 are cut off aftera time period while the lamp driving circuit 505 has been activatedsuccessfully. After that, the lamp driving circuit 505 has a sufficientdrive capability for driving the LED lamp to emit light.

It is worth noting that the rectifying circuit 810 shown in FIG. 50C mayreplace the rectifying circuit 510 of the present embodiment shown inFIG. 59C instead of the rectifying circuit 540. Wherein, the rectifyingunit 815 of the rectifying circuit 810 is coupled to the pins 501 and502 and the terminal adapter circuit 541 thereof is coupled to therectifying output terminals 511 and 512. The arrangement of the twoballast-compatible circuits 1540 is also changed to be coupledrespectively between the pin 503 and the half-wave node 819 and betweenthe pin 504 and the half-wave node 819.

FIG. 59D is a schematic diagram of a ballast-compatible circuitaccording to an embodiment of the present invention, which is applicableto the embodiments shown in FIGS. 59A and 59B and the describedmodification thereof.

A ballast-compatible circuit 1640 comprises resistors 1643, 1645, 1648and 1650, capacitors 1644 and 1649, diodes 1647 and 1652, bipolarjunction transistors (BJT) 1646 and 1651, a ballast-compatible circuitterminal 1641 and a ballast-compatible circuit terminal 1642. One end ofthe resistor 1645 is coupled to the ballast-compatible circuit terminal1641, and the other end is coupled to an emitter of the BJT 1646. Acollector of the BJT 1646 is coupled to a positive end of the diode1647, and a negative end thereof is coupled to the ballast-compatiblecircuit terminal 1642. The resistor 1643 and the capacitor 1644 areconnected in series with each other and coupled between the emitter andthe collector of the BJT 1646, and the connection node of the resistor1643 and the capacitor 1644 is coupled to a base of the BJT 1646. Oneend of the resistor 1650 is coupled to the ballast-compatible circuitterminal 1642, and the other end is coupled to an emitter of the BJT1651. A collector of the BJT 1651 is coupled to a positive end of thediode 1652, and a negative end thereof is coupled to theballast-compatible circuit terminal 1641. The resistor 1648 and thecapacitor 1649 are connected in series with each other and coupledbetween the emitter and the collector of the BJT 1651, and theconnection node of the resistor 1648 and the capacitor 1649 is coupledto a base of the BJT 1651.

In an initial stage upon the lamp driving circuit 505, e.g. electronicballast, being activated, voltages across the capacitors 1644 and 1649are about zero. At this time, the BJTs 1646 and 1651 are in conductingstate and the bases thereof allow currents to flow through. Therefore,in an initial stage upon activation of the lamp driving circuit 505, theballast-compatible circuits 1640 are in conducting state. The AC drivingsignal charges the capacitor 1644 through the resistor 1643 and thediode 1647, and charges the capacitor 1649 through the resistor 1648 andthe diode 1652. After a time period, the voltages across the capacitors1644 and 1649 reach certain voltages so as to reduce the voltages of theresistors 1643 and 1648, thereby cutting off the BJTs 1646 and 1651,i.e., the states of the BJTs 1646 and 1651 are cutoff states. At thistime, the state of the ballast-compatible circuit 1640 is changed to thecutoff state. Thereby, the internal capacitor(s) and inductor(s) do notaffect in Q-factor of the lamp driving circuit 505 at the beginning forensuring the lamp driving circuit activating. Hence, theballast-compatible circuit 1640 improves the compatibility of LED lampwith the electronic ballast.

In summary, the two ballast-compatible circuits of the present inventionare respectively coupled between a connection node of the rectifyingcircuit and the filtering circuit (i.e., the rectifying output terminal511 or 512) and the pin 501 and between the connection node and the pin502, or coupled between the connection node and the pin 503 and theconnection node and the pin 504. The two ballast-compatible circuitsconduct for an objective delay upon the external driving signal beinginput into the LED tube lamp, and then are cut off for enhancing thecompatibility of the LED lamp with the electronic ballast.

FIG. 60A is a block diagram of a power supply module in an LED tube lampaccording to an embodiment of the present invention. Compared to thatshown in FIG. 49E, the present embodiment comprises the rectifyingcircuits 510 and 540, the filtering circuit 520, and the LED drivingmodule 530, and further comprises two filament-simulating circuits 1560.The filament-simulating circuits 1560 are respectively coupled betweenthe pins 501 and 502 and coupled between the pins 503 and 504, forimproving a compatibility with a lamp driving circuit having filamentdetection function, e.g.: program-start ballast.

In an initial stage upon the lamp driving circuit having filamentdetection function being activated, the lamp driving circuit willdetermine whether the filaments of the lamp operate normally or are inan abnormal condition of short-circuit or open-circuit. When determiningthe abnormal condition of the filaments, the lamp driving circuit stopsoperating and enters a protection state. In order to avoid that the lampdriving circuit erroneously determines the LED tube lamp to be abnormaldue to the LED tube lamp having no filament, the two filament-simulatingcircuits 1560 simulate the operation of actual filaments of afluorescent tube to have the lamp driving circuit enter into a normalstate to start the LED lamp normally.

FIG. 60B is a schematic diagram of a filament-simulating circuitaccording to an embodiment of the present invention. Thefilament-simulating circuit comprises a capacitor 1663 and a resistor1665 connected in parallel, and two ends of the capacitor 1663 and twoends of the resistor 1665 are re respectively coupled to filamentsimulating terminals 1661 and 1662. Referring to FIG. 60A, the filamentsimulating terminals 1661 and 1662 of the two filament simulating 1660are respectively coupled to the pins 501 and 502 and the pins 503 and504. During the filament detection process, the lamp driving circuitoutputs a detection signal to detect the state of the filaments. Thedetection signal passes the capacitor 1663 and the resistor 1665 and sothe lamp driving circuit determines that the filaments of the LED lampare normal.

In addition, a capacitance value of the capacitor 1663 is low and so acapacitive reactance (equivalent impedance) of the capacitor 1663 is farlower than an impedance of the resistor 1665 due to the lamp drivingcircuit outputting a high-frequency alternative current (AC) signal todrive LED lamp. Therefore, the filament-simulating circuit 1660 consumesfairly low power when the LED lamp operates normally, and so it almostdoes not affect the luminous efficiency of the LED lamp.

FIG. 60C is a schematic block diagram including a filament-simulatingcircuit according to an embodiment of the present invention. In thepresent embodiment, the filament-simulating circuit 1660 replaces theterminal adapter circuit 541 of the rectifying circuit 810 shown in FIG.50C, which is adopted as the rectifying circuit 510 or/and 540 in theLED lamp. For example, the filament-simulating circuit 1660 of thepresent embodiment has both of filament simulating and terminal adaptingfunctions. Referring to FIG. 60A, the filament simulating terminals 1661and 1662 of the filament-simulating circuit 1660 are respectivelycoupled to the pins 501 and 502 or/and pins 503 and 504. The half-wavenode 819 of rectifying unit 815 in the rectifying circuit 810 is coupledto the filament simulating terminal 1662.

FIG. 60D is a schematic block diagram including a filament-simulatingcircuit according to another embodiment of the present invention.Compared to that shown in FIG. 60C, the half-wave node is changed to becoupled to the filament simulating terminal 1661, and thefilament-simulating circuit 1660 in the present embodiment still hasboth of filament simulating and terminal adapting functions.

FIG. 60E is a schematic diagram of a filament-simulating circuitaccording to another embodiment of the present invention. Afilament-simulating circuit 1760 comprises capacitors 1763 and 1764, andthe resistors 1765 and 1766. The capacitors 1763 and 1764 are connectedin series and coupled between the filament simulating terminals 1661 and1662. The resistors 1765 and 1766 are connected in series and coupledbetween the filament simulating terminals 1661 and 1662. Furthermore,the connection node of capacitors 1763 and 1764 is coupled to that ofthe resistors 1765 and 1766. Referring to FIG. 60A, the filamentsimulating terminals 1661 and 1662 of the filament-simulating circuit1760 are respectively coupled to the pins 501 and 502 and the pins 503and 504. When the lamp driving circuit outputs the detection signal fordetecting the state of the filament, the detection signal passes thecapacitors 1763 and 1764 and the resistors 1765 and 1766 so that thelamp driving circuit determines that the filaments of the LED lamp arenormal.

It is worth noting that in some embodiments, capacitance values of thecapacitors 1763 and 1764 are low and so a capacitive reactance of theserially connected capacitors 1763 and 1764 is far lower than animpedance of the serially connected resistors 1765 and 1766 due to thelamp driving circuit outputting the high-frequency AC signal to driveLED lamp. Therefore, the filament-simulating circuit 1760 consumesfairly low power when the LED lamp operates normally, and so it almostdoes not affect the luminous efficiency of the LED lamp. Moreover, anyone of the capacitor 1763 and the resistor 1765 is short circuited or isan open circuit, or any one of the capacitor 1764 and the resistor 1766is short circuited or is an open circuit, the detection signal stillpasses through the filament-simulating circuit 1760 between the filamentsimulating terminals 1661 and 1662. Therefore, the filament-simulatingcircuit 1760 still operates normally when any one of the capacitor 1763and the resistor 1765 is short circuited or is an open circuit or anyone of the capacitor 1764 and the resistor 1766 is short circuited or isan open circuit, and so it has quite high fault tolerance.

FIG. 60F is a schematic block diagram including a filament-simulatingcircuit according to an embodiment of the present invention. In thepresent embodiment, the filament-simulating circuit 1860 replaces theterminal adapter circuit 541 of the rectifying circuit 810 shown in FIG.50C, which is adopted as the rectifying circuit 510 or/and 540 in theLED lamp. For example, the filament-simulating circuit 1860 of thepresent embodiment has both of filament simulating and terminal adaptingfunctions. An impedance of the filament-simulating circuit 1860 has anegative temperature coefficient (NTC), i.e., the impedance at a highertemperature is lower than that at a lower temperature. In the presentembodiment, the filament-simulating circuit 1860 comprises two NTCresistors 1863 and 1864 connected in series and coupled to the filamentsimulating terminals 1661 and 1662. Referring to FIG. 60A, the filamentsimulating terminals 1661 and 1662 are respectively coupled to the pins501 and 502 or/and the pins 503 and 504. The half-wave node 819 of therectifying unit 815 in the rectifying circuit 810 is coupled to aconnection node of the NTC resistors 1863 and 1864.

When the lamp driving circuit outputs the detection signal for detectingthe state of the filament, the detection signal passes the NTC resistors1863 and 1864 so that the lamp driving circuit determines that thefilaments of the LED lamp are normal. The impedance of the seriallyconnected NTC resistors 1863 and 1864 is gradually decreased with thegradually increasing of temperature due to the detection signal or apreheat process. When the lamp driving circuit enters into the normalstate to start the LED lamp normally, the impedance of the seriallyconnected NTC resistors 1863 and 1864 is decreased to a relative lowvalue and so the power consumption of the filament simulation circuit1860 is lower.

An exemplary impedance of the filament-simulating circuit 1860 can be 10ohms or more at room temperature (25 degrees Celsius) and may bedecreased to a range of about 2-10 ohms when the lamp driving circuitenters into the normal state. It may be preferred that the impedance ofthe filament-simulating circuit 1860 is decreased to a range of about3-6 ohms when the lamp driving circuit enters into the normal state.

FIG. 61A is a block diagram of a power supply module in an LED tube lampaccording to an embodiment of the present invention. Compared to thatshown in FIG. 49E, the present embodiment comprises the rectifyingcircuits 510 and 540, the filtering circuit 520, and the LED drivingmodule 530, and further comprises an over voltage protection (OVP)circuit 1570. The OVP circuit 1570 is coupled to the filtering outputterminals 521 and 522 for detecting the filtered signal. The OVP circuit1570 clamps the level of the filtered signal when determining the levelthereof higher than a defined OVP value. Hence, the OVP circuit 1570protects the LED driving module 530 from damage due to an OVP condition.The rectifying circuit 540 may be omitted and is therefore depicted by adotted line.

FIG. 61B is a schematic diagram of an overvoltage protection (OVP)circuit according to an embodiment of the present invention. The OVPcircuit 1670 comprises a voltage clamping diode 1671, such as zenerdiode, coupled to the filtering output terminals 521 and 522. Thevoltage clamping diode 1671 is conducted to clamp a voltage differenceat a breakdown voltage when the voltage difference of the filteringoutput terminals 521 and 522 (i.e., the level of the filtered signal)reaches the breakdown voltage. The breakdown voltage may be preferred ina range of about 40 V to about 100 V, and more preferred in a range ofabout 55 V to about 75V.

FIG. 62A is a block diagram of a power supply module in an LED tube lampaccording to an embodiment of the present invention. Compared to thatshown in FIG. 60A, the present embodiment comprises the rectifyingcircuits 510 and 540, the filtering circuit 520, the LED driving module530 and the two filament-simulating circuits 1560, and further comprisesa ballast detection circuit 1590. The ballast detection circuit 1590 maybe coupled to any one of the pins 501, 502, 503 and 504 and acorresponding rectifying circuit of the rectifying circuits 510 and 540.In the present embodiment, the ballast detection circuit 1590 is coupledbetween the pin 501 and the rectifying circuit 510.

The ballast detection circuit 1590 detects the AC driving signal or asignal input through the pins 501, 502, 503 and 504, and determineswhether the input signal is provided by an electric ballast based on thedetected result.

FIG. 62B is a block diagram of a power supply module in an LED tube lampaccording to an embodiment of the present invention. Compared to thatshown in FIG. 62A, the rectifying circuit 810 shown in FIG. 50C replacesthe rectifying circuit 510. The ballast detection circuit 1590 iscoupled between the rectifying unit 815 and the terminal adapter circuit541. One of the rectifying unit 815 and the terminal adapter circuit 541is coupled to the pines 503 and 504, and the other one is coupled to therectifying output terminal 511 and 512. In the present embodiment, therectifying unit 815 is coupled to the pins 503 and 504, and the terminaladapter circuit 541 is coupled to the rectifying output terminal 511 and512. Similarly, the ballast detection circuit 1590 detects the signalinput through the pins 503 and 504 for determining the input signalwhether provided by an electric ballast according to the frequency ofthe input signal.

In addition, the rectifying circuit 810 may replace the rectifyingcircuit 510 instead of the rectifying circuit 540, and the ballastdetection circuit 1590 is coupled between the rectifying unit 815 andthe terminal adapter circuit 541 in the rectifying circuit 510.

FIG. 62C is a block diagram of a ballast detection circuit according toan embodiment of the present invention. The ballast detection circuit1590 comprises a detection circuit 1590 a and a switch circuit 1590 b.The switch circuit 1590 b is coupled to switch terminals 1591 and 1592.The detection circuit 1590 a is coupled to the detection terminals 1593and 1594 for detecting a signal transmitted through the detectionterminals 1593 and 1594. Alternatively, the switch terminals 1591 and1592 serves as the detection terminals and the detection terminals 1593and 1594 are omitted. For example, in certain embodiments, the switchcircuit 1590 b and the detection circuit 1590 a are commonly coupled tothe switch terminals 1591 and 1592, and the detection circuit 1590 adetects a signal transmitted through the switch terminals 1591 and 1592.Hence, the detection terminals 1593 and 1594 are depicted by dottedlines.

FIG. 62D is a schematic diagram of a ballast detection circuit accordingto an embodiment of the present invention. The ballast detection circuit1690 comprises a detection circuit 1690 a and a switch circuit 1690 b,and is coupled between the switch terminals 1591 and 1592. The detectioncircuit 1690 a comprises a symmetrical trigger diode 1691, resistors1692 and 1696 and capacitors 1693, 1697 and 1698. The switch circuit1690 b comprises a TRIAC 1699 and an inductor 1694.

The capacitor 1698 is coupled between the switch terminals 1591 and 1592for generating a detection voltage in response to a signal transmittedthrough the switch terminals 1591 and 1592. When the signal is a highfrequency signal, the capacitive reactance of the capacitor 1698 isfairly low and so the detection voltage generated thereby is quite high.The resistor 1692 and the capacitor 1693 are connected in series andcoupled between two ends of the capacitor 1698. The serially connectedresistor 1692 and the capacitor 1693 is used to filter the detectionsignal generated by the capacitor 1698 and generates a filtereddetection signal at a connection node thereof. The filter function ofthe resistor 1692 and the capacitor 1693 is used to filter highfrequency noise in the detection signal for preventing the switchcircuit 1690 b from misoperation due to the high frequency noise. Theresistor 1696 and the capacitor 1697 are connected in series and coupledbetween two ends of the capacitor 1693, and transmit the filtereddetection signal to one end of the symmetrical trigger diode 1691. Theserially connected resistor 1696 and capacitor 1697 performs secondfiltering of the filtered detection signal to enhance the filter effectof the detection circuit 1690 a. Based on requirement for filteringlevel of different application, the capacitor 1697 may be omitted andthe end of the symmetrical trigger diode 1691 is coupled to theconnection node of the resistor 1692 and the capacitor 1693 through theresistor 1696. Alternatively, both of the resistor 1696 and thecapacitor 1697 are omitted and the end of the symmetrical trigger diode1691 is directly coupled to the connection node of the resistor 1692 andthe capacitor 1693. Therefore, the resistor 1696 and the capacitor 1697are depicted by dotted lines. The other end of the symmetrical triggerdiode 1691 is coupled to a control end of the TRIAC 1699 of the switchcircuit 1690 b. The symmetrical trigger diode 1691 determines whether togenerate a control signal 1695 to trigger the TRIAC 1699 on according toa level of a received signal. A first end of the TRIAC 1699 is coupledto the switch terminal 1591 and a second end thereof is coupled to theswitch terminal through the inductor 1694. The inductor 1694 is used toprotect the TRIAC 1699 from damage due to a situation where the signaltransmitted into the switch terminals 1591 and 1592 is over a maximumrate of rise of Commutation Voltage, a peak repetitive forward(off-state) voltage or a maximum rate of change of current.

When the switch terminals 1591 and 1592 receive a low frequency signalor a DC signal, the detection signal generated by the capacitor 1698 ishigh enough to make the symmetrical trigger diode 1691 generate thecontrol signal 1695 to trigger the TRIAC 1699 on. At this time, theswitch terminals 1591 and 1592 are shorted to bypass the circuit(s)connected in parallel with the switch circuit 1690 b, such as a circuitcoupled between the switch terminals 1591 and 1592, the detectioncircuit 1690 a and the capacitor 1698.

In some embodiments, when the switch terminals 1591 and 1592 receive ahigh frequency AC signal, the detection signal generated by thecapacitor 1698 is not high enough to make the symmetrical trigger diode1691 generate the control signal 1695 to trigger the TRIAC 1699 on. Atthis time, the TRIAC 1699 is cut off and so the high frequency AC signalis mainly transmitted through external circuit or the detection circuit1690 a.

Hence, the ballast detection circuit 1690 can determine whether theinput signal is a high frequency AC signal provided by an electricballast. If yes, the high frequency AC signal is transmitted through theexternal circuit or the detection circuit 1690 a; if no, the inputsignal is transmitted through the switch circuit 1690 b, bypassing theexternal circuit and the detection circuit 1690 a.

It is worth noting that the capacitor 1698 may be replaced by externalcapacitor(s), such as at least one capacitor in the terminal adaptercircuits shown in FIG. 51A-C. Therefore, the capacitor 1698 may beomitted and be therefore depicted by a dotted line.

FIG. 62E is a schematic diagram of a ballast detection circuit accordingto an embodiment of the present invention. The ballast detection circuit1790 comprises a detection circuit 1790 a and a switch circuit 1790 b.The switch circuit 1790 b is coupled between the switch terminals 1591and 1592. The detection circuit 1790 a is coupled between the detectionterminals 1593 and 1594. The detection circuit 1790 a comprisesinductors 1791 and 1792 with mutual induction, capacitor 1793 and 1796,a resistor 1794 and a diode 1797. The switch circuit 1790 b comprises aswitch 1799. In the present embodiment, the switch 1799 is a P-typeDepletion Mode MOSFET, which is cut off when the gate voltage is higherthan a threshold voltage and conducted when the gate voltage is lowerthan the threshold voltage.

The inductor 1792 is coupled between the detection terminals 1593 and1594 and induces a detection voltage in the inductor 1791 based on acurrent signal flowing through the detection terminals 1593 and 1594.The level of the detection voltage is varied with the frequency of thecurrent signal, and may be increased with the increasing of thatfrequency and reduced with the decreasing of that frequency.

In some embodiments, when the signal is a high frequency signal, theinductive reactance of the inductor 1792 is quite high and so theinductor 1791 induces the detection voltage with a quite high level.When the signal is a low frequency signal or a DC signal, the inductivereactance of the inductor 1792 is quite low and so the inductor 1791induces the detection voltage with a quite high level. One end of theinductor 1791 is grounded. The serially connected capacitor 1793 andresistor 1794 is connected in parallel with the inductor 1791. Thecapacitor 1793 and resistor 1794 receive the detection voltage generatedby the inductor 1791 and filter a high frequency component of thedetection voltage to generate a filtered detection voltage. The filtereddetection voltage charges the capacitor 1796 through the diode 1797 togenerate a control signal 1795. Due to the diode 1797 providing aone-way charge for the capacitor 1796, the level of control signalgenerated by the capacitor 1796 is the maximum value of the detectionvoltage. The capacitor 1796 is coupled to the control end of the switch1799. First and second ends of the switch 1799 are respectively coupledto the switch terminals 1591 and 1592.

When the signal received by the detection terminal 1593 and 1594 is alow frequency signal or a DC signal, the control signal 1795 generatedby the capacitor 1796 is lower than the threshold voltage of the switch1799 and so the switch 1799 are conducted. At this time, the switchterminals 1591 and 1592 are shorted to bypass the external circuit(s)connected in parallel with the switch circuit 1790 b, such as the leastone capacitor in the terminal adapter circuits show in FIG. 51A-c.

When the signal received by the detection terminal 1593 and 1594 is ahigh frequency signal, the control signal 1795 generated by thecapacitor 1796 is higher than the threshold voltage of the switch 1799and so the switch 1799 are cut off. At this time, the high frequencysignal is transmitted by the external circuit(s).

Hence, the ballast detection circuit 1790 can determine whether theinput signal is a high frequency AC signal provided by an electricballast. If yes, the high frequency AC signal is transmitted through theexternal circuit(s); if no, the input signal is transmitted through theswitch circuit 1790 b, bypassing the external circuit.

Next, exemplary embodiments of the conduction (bypass) and cut off (notbypass) operations of the switch circuit in the ballast detectioncircuit of an LED lamp will be illustrated. For example, the switchterminals 1591 and 1592 are coupled to a capacitor connected in serieswith the LED lamp, e.g., a signal for driving the LED lamp also flowsthrough the capacitor. The capacitor may be disposed inside the LED lampto be connected in series with internal circuit(s) or outside the LEDlamp to be connected in series with the LED lamp. Referring to FIG. 49A,49B, or 49D, the AC power supply 508 provides a low voltage and lowfrequency AC driving signal as an external driving signal to drive theLED tube lamp 500 while the lamp driving circuit 505 does not exist. Atthis moment, the switch circuit of the ballast detection circuit isconducted, and so the alternative driving signal is provided to directlydrive the internal circuits of the LED tube lamp 500. When the lampdriving circuit 505 exists, the lamp driving circuit 505 provides a highvoltage and high frequency AC driving signal as an external drivingsignal to drive the LED tube lamp 500. At this moment, the switchcircuit of the ballast detection circuit is cut off, and so thecapacitor is connected in series with an equivalent capacitor of theinternal circuit(s) of the LED tube lamp for forming a capacitivevoltage divider network. Thereby, a division voltage applied in theinternal circuit(s) of the LED tube lamp is lower than the high voltageand high frequency AC driving signal, e.g.: the division voltage is in arange of 100-270V, and so no over voltage causes the internal circuit(s)damage. Alternatively, the switch terminals 1591 and 1592 is coupled tothe capacitor(s) of the terminal adapter circuit shown in FIG. 51A toFIG. 51C to have the signal flowing through the half-wave node as wellas the capacitor(s), e.g., the capacitor 642 in FIG. 51A, or thecapacitor 842 in FIG. 51C. When the high voltage and high frequency ACsignal generated by the lamp driving circuit 505 is input, the switchcircuit is cut off and so the capacitive voltage divider is performed;and when the low frequency AC signal of the commercial power or thedirect current of battery is input, the switch circuit bypasses thecapacitor(s).

It is worth noting that the switch circuit may have plural switch unitto have two or more switch terminal for being connected in parallel withplural capacitors, (e.g., the capacitors 645 and 645 in FIG. 51A, thecapacitors 643, 645 and 646 in FIG. 51A, the capacitors 743 and 744or/and the capacitors 745 and 746 in FIG. 50B, the capacitors 843 and844 in FIG. 51C, the capacitors 845 and 846 in FIG. 51C, the capacitors842, 843 and 844 in FIG. 51C, the capacitors 842, 845 and 846 in FIG.51C, and the capacitors 842, 843, 844, 845 and 846 in FIG. 51C) forbypassing the plural capacitor.

In addition, the ballast detection circuit of the present invention canbe used in conjunction with the mode switching circuits shown in FIG.57A-57I. The switch circuit of the ballast detection circuit is replacedwith the mode switching circuit. The detection circuit of the ballastdetection circuit is coupled to one of the pins 501, 502, 503 and 504for detecting the signal input into the LED lamp through the pins 501,502, 503 and 504. The detection circuit generates a control signal tocontrol the mode switching circuit being at the first mode or the secondmode according to whether the signal is a high frequency, low frequencyor DC signal, i.e., the frequency of the signal.

For example, when the signal is a high frequency signal and higher thana defined mode switch frequency, such as the signal provided by the lampdriving circuit 505, the control signal generated by the detectioncircuit makes the mode switching circuit be at the second mode fordirectly inputting the filtered signal into the LED module. When thesignal is a low frequency signal or a direct signal and lower than thedefined mode switch frequency, such as the signal provided by thecommercial power or the battery, the control signal generated by thedetection circuit makes the mode switching circuit be at the first modefor directly inputting the filtered signal into the driving circuit.

FIG. 63A is a block diagram of a power supply module in an LED tube lampaccording to an embodiment of the present invention. Compared to thatshown in FIG. 60A, the present embodiment comprises the rectifyingcircuits 510 and 540, the filtering circuit 520, the LED driving module530, the two filament-simulating circuits 1560, and further comprises anauxiliary power module 2510. The auxiliary power module 2510 is coupledbetween the filtering output terminal 521 and 522. The auxiliary powermodule 2510 detects the filtered signal in the filtering outputterminals 521 and 522, and determines whether providing an auxiliarypower to the filtering output terminals 521 and 522 based on thedetected result. When the supply of the filtered signal is stopped or alevel thereof is insufficient, i.e., when a drive voltage for the LEDmodule is below a defined voltage, the auxiliary power module providesauxiliary power to keep the LED driving module 530 continuing to emitlight. The defined voltage is determined according to an auxiliary powervoltage of the auxiliary power module 2510. The rectifying circuit 540and the filament-simulating circuit 1560 may be omitted and aretherefore depicted by dotted lines.

FIG. 63B is a block diagram of a power supply module in an LED tube lampaccording to an embodiment of the present invention. Compared to thatshown in FIG. 63A, the present embodiment comprises the rectifyingcircuits 510 and 540, the filtering circuit 520, the LED driving module530, the two filament-simulating circuits 1560, and the LED drivingmodule 530 further comprises the driving circuit 1530 and the LED module630. The auxiliary power module 2510 is coupled between the drivingoutput terminals 1521 and 1522.

The auxiliary power module 2510 detects the driving signal in thedriving output terminals 1521 and 1522, and determines whether toprovide an auxiliary power to the driving output terminals 1521 and 1522based on the detected result. When the driving signal is no longer beingsupplied or a level thereof is insufficient, the auxiliary power moduleprovides the auxiliary power to keep the LED module 630 continuouslylight. The rectifying circuit 540 and the filament-simulating circuit1560 may be omitted and are therefore depicted by dotted lines.

FIG. 63C is a schematic diagram of an auxiliary power module accordingto an embodiment of the present invention. The auxiliary power module2610 comprises an energy storage unit 2613 and a voltage detectioncircuit 2614. The auxiliary power module further comprises an auxiliarypower positive terminal 2611 and an auxiliary power negative terminal2612 for being respectively coupled to the filtering output terminals521 and 522 or the driving output terminals 1521 and 1522. The voltagedetection circuit 2614 detects a level of a signal at the auxiliarypower positive terminal 2611 and the auxiliary power negative terminal2612 to determine whether releasing outward the power of the energystorage unit 2613 through the auxiliary power positive terminal 2611 andthe auxiliary power negative terminal 2612.

In the present embodiment, the energy storage unit 2613 is a battery ora supercapacitor. When a voltage difference of the auxiliary powerpositive terminal 2611 and the auxiliary power negative terminal 2612(the drive voltage for the LED module) is higher than the auxiliarypower voltage of the energy storage unit 2613, the voltage detectioncircuit 2614 charges the energy storage unit 2613 by the signal in theauxiliary power positive terminal 2611 and the auxiliary power negativeterminal 2612. When the drive voltage is lower than the auxiliary powervoltage, the energy storage unit 2613 releases the stored energy outwardthrough the auxiliary power positive terminal 2611 and the auxiliarypower negative terminal 2612.

The voltage detection circuit 2614 comprises a diode 2615, a bipolarjunction transistor (BJT) 2616 and a resistor 2617. A positive end ofthe diode 2615 is coupled to a positive end of the energy storage unit2613 and a negative end of the diode 2615 is coupled to the auxiliarypower positive terminal 2611. The negative end of the energy storageunit 2613 is coupled to the auxiliary power negative terminal 2612. Acollector of the BJT 2616 is coupled to the auxiliary power positiveterminal 2611, and the emitter thereof is coupled to the positive end ofthe energy storage unit 2613. One end of the resistor 2617 is coupled tothe auxiliary power positive terminal 2611 and the other end is coupledto a base of the BJT 2616. When the collector of the BJT 2616 is acut-in voltage higher than the emitter thereof, the resistor 2617conducts the BJT 2616. When the power source provides power to the LEDtube lamp normally, the energy storage unit 2613 is charged by thefiltered signal through the filtering output terminals 521 and 522 andthe conducted BJT 2616 or by the driving signal through the drivingoutput terminals 1521 and 1522 and the conducted BJT 2616 unit that thecollector-emitter voltage of the BJT 2616 is lower than or equal to thecut-in voltage. When the filtered signal or the driving signal is nolonger being supplied or the level thereof is insufficient, the energystorage unit 2613 provides power through the diode 2615 to keep the LEDdriving module 530 or the LED module 630 continuously light.

It is worth noting that in some embodiments, the maximum voltage of thecharged energy storage unit 2613 is the cut-in voltage of the BJT 2616lower than a voltage difference applied between the auxiliary powerpositive terminal 2611 and the auxiliary power negative terminal 2612.The voltage difference provided between the auxiliary power positiveterminal 2611 and the auxiliary power negative terminal 2612 is aturn-on voltage of the diode 2615 lower than the voltage of the energystorage unit 2613. Hence, when the auxiliary power module 2610 providespower, the voltage applied at the LED module 630 is lower (about the sumof the cut-in voltage of the BJT 2616 and the turn-on voltage of thediode 2615). In the embodiment shown in the FIG. 63B, the brightness ofthe LED module 630 is reduced when the auxiliary power module suppliespower thereto. Thereby, when the auxiliary power module is applied to anemergency lighting system or a constant lighting system, the userrealizes the main power supply, such as commercial power, is abnormaland then performs necessary precautions therefor.

FIG. 64 is a block diagram of a power supply module in an LED tube lampaccording to an embodiment of the present invention. Compared to theabove mentioned embodiments, the circuits for driving the LED module isinstalled outside of the LED tube lamp. For example, the LED tube lamp3500 is driven to emit light by an external driving power 3530 throughexternal driving terminals 3501 and 3502. The LED tube lamp 3500comprises the LED module 630 and a current control circuit 3510, anddoes not comprise the rectifying circuit, filtering circuit and thedriving circuit. In the present embodiment, the external drivingterminals 3501 and 3502 serve as the pins 501 and 502 shown in FIG. 49Aand FIG. 49B.

The external driving power 3530 may be directly connected with thecommercial power or the ballast for receiving power and converting intoan external driving signal to input into the LED tube lamp 3500 throughthe external driving terminals 3501 and 3502. The external drivingsignal may be a DC signal, and may preferably be a stable DC currentsignal. Under a normal condition, the current control circuit 3510conducts to have a current flowing through and driving the LED module630 to emit light. The current control circuit 3510 may further detectthe current of the LED module 630 for performing a steady current orvoltage control, and have a function of ripple filter. Under an abnormalcondition, the current control circuit 3510 is cut off to stop inputtingthe power of the external driving power 3530 into the LED module 630 andenters into a protection state.

When the current control circuit 3510 determines that the current of theLED module 630 is lower than a defined current or a minimum current of adefined current range, the current control circuit 3510 is completelyconducted, i.e., the impedance of the current control circuit 3510 comesdown a minimum value.

When the current control circuit 3510 determines that the current of theLED module 630 is higher than a defined current or a maximum current ofa defined current range, the current control circuit 3510 is cutoff tostop inputting power into the LED tube lamp 3500. The maximum current ofa defined current range is in some embodiments set at a value about 30%higher than a rated current of the LED module 630. Thereby, the currentcontrol circuit 3510 can keep the brightness of the LED lamp as much aspossible when a driving capability of the external driving power 3530 isreduced. Furthermore, the current control circuit 3510 can prevent theLED module 630 from over current when the driving capability of theexternal driving power 3530 is abnormally increased. Hence, the currentcontrol circuit 3510 has a function of over-current protection.

It is worth noting that the external driving power 3530 may be a DCvoltage signal. Under a normal condition, the current control circuit3510 stabilizes the current of the LED module 630 or controls thecurrent linearly, e.g, the current of the LED module 630 is variedlinearly with a level of the DC voltage signal. For controlling thecurrent of the LED module at a current value or linearly, a voltagecross the current control circuit 3510 is increased with the level ofthe DC voltage signal provided by the external driving power 3530 and apower consumption thereof is also increased. The current control circuit3510 may have a temperature detector. When the level of the DC voltagesignal provided by the external driving power 3530 is over a highthreshold, the current control circuit 3510 enters into a state of overtemperature protection to stop inputting power of the external drivingpower 3530 into the LED tube lamp 3500. For example, when thetemperature detector detects the temperature of the current controlcircuit 3510 at 120° C., the current control circuit 3510 enters intothe state of over temperature protection. Thereby, the current controlcircuit 3510 has both over temperature and over voltage protections.

In some embodiments, due to the external driving power, the length ofthe end caps are shortened. For ensuring the total length of the LEDtube lamp to conform to a standard for a fluorescent lamp, a length ofthe lamp tube is lengthened to compensate the shortened length of theend caps. Due to the lengthened length of the lamp tube, the LED lightstring is correspondingly lengthened. Therefore, the interval ofadjacent two LEDs disposed on the LED light string becomes greater underthe same illuminance requirement. The greater interval increases theheat dissipation of the LEDs and so the operation temperature of theLEDs is lowered and the life-span of the LED tube lamp is extended.

Referring to FIG. 37, in one embodiment, each of the LED light sources202 may be provided with an LED lead frame 202 b having a recess 202 a,and an LED chip 18 disposed in the recess 202 a. The recess 202 a may beone or more than one in amount. The recess 202 a may be filled withphosphor covering the LED chip 18 to convert emitted light therefrominto a desired light color. Compared with a conventional LED chip beinga substantial square, the LED chip 18 in this embodiment may bepreferably rectangular with the dimension of the length side to thewidth side at a ratio ranges generally from about 2:1 to about 10:1, insome embodiments from about 2.5:1 to about 5:1, and in some moredesirable embodiments from about 3:1 to about 4.5:1. Moreover, the LEDchip 18 is in some embodiments arranged with its length directionextending along the length direction of the lamp tube 1 to increase theaverage current density of the LED chip 18 and improve the overallillumination field shape of the lamp tube 1. The lamp tube 1 may have anumber of LED light sources 202 arranged into one or more rows, and eachrow of the LED light sources 202 is arranged along the length direction(Y-direction) of the lamp tube 1.

Referring again to FIG. 37, the recess 202 a is enclosed by two parallelfirst sidewalls 15 and two parallel second sidewalls 16 with the firstsidewalls 15 being lower than the second sidewalls 16. The two firstsidewalls 15 are arranged to be located along a length direction(Y-direction) of the lamp tube 1 and extend along the width direction(X-direction) of the lamp tube 1, and two second sidewalls 16 arearranged to be located along a width direction (X-direction) of the lamptube 1 and extend along the length direction (Y-direction) of the lamptube 1. The extending direction of the first sidewalls 15 may besubstantially rather than exactly parallel to the width direction(X-direction) of the lamp tube 1, and the first sidewalls may havevarious outlines such as zigzag, curved, wavy, and the like. Similarly,the extending direction of the second sidewalls 16 may be substantiallyrather than exactly parallel to the length direction (Y-direction) ofthe lamp tube 1, and the second sidewalls may have various outlines suchas zigzag, curved, wavy, and the like. In one row of the LED lightsources 202, the arrangement of the first sidewalls 15 and the secondsidewalls 16 for each LED light source 202 can be same or different.

Having the first sidewalls 15 being lower than the second sidewalls 16and proper distance arrangement, the LED lead frame 202 b allowsdispersion of the light illumination to cross over the LED lead frame202 b without causing uncomfortable visual feeling to people observingthe LED tube lamp along the Y-direction. In some embodiments, the firstsidewalls 15 may not be lower than the second sidewalls, however, and inthis case the rows of the LED light sources 202 are more closelyarranged to reduce grainy effects. On the other hand, when a user of theLED tube lamp observes the lamp tube thereof along the X-direction, thesecond sidewalls 16 also can block user's line of sight from seeing theLED light sources 202, and which reduces unpleasing grainy effects.

Referring again to FIG. 37, the first sidewalls 15 each includes aninner surface 15 a facing toward outside of the recess 202 a. The innersurface 15 a may be designed to be an inclined plane such that the lightillumination easily crosses over the first sidewalls 15 and spreads out.The inclined plane of the inner surface 15 a may be flat or cambered orcombined shape. In some embodiments, when the inclined plane is flat,the slope of the inner surface 15 a ranges from about 30 degrees toabout 60 degrees. Thus, an included angle between the bottom surface ofthe recess 202 a and the inner surface 15 a may range from about 120 toabout 150 degrees. In some embodiments, the slope of the inner surface15 a ranges from about 15 degrees to about 75 degrees, and the includedangle between the bottom surface of the recess 202 a and the innersurface 15 a ranges from about 105 degrees to about 165 degrees.

There may be one row or several rows of the LED light sources 202arranged in a length direction (Y-direction) of the lamp tube 1. In caseof one row, in one embodiment, the second sidewalls 16 of the LED leadframes 202 b of all of the LED light sources 202 located in the same roware disposed in same straight lines to respectively form two walls forblocking the user's line of sight seeing the LED light sources 202. Incase of several rows, in some embodiments, only the LED lead frames 202b of the LED light sources 202 disposed in the outermost two rows aredisposed in same straight lines to respectively form walls for blockinguser's line of sight seeing the LED light sources 202. In case ofseveral rows, it may be required only that the LED lead frames 202 b ofthe LED light sources 202 disposed in the outermost two rows aredisposed in same straight lines to respectively from walls for blockinguser's line of sight seeing the LED light sources 202. The LED leadframes 202 b of the LED light sources 202 disposed in the other rows canhave different arrangements. For example, as far as the LED lightsources 202 located in the middle row (third row) are concerned, the LEDlead frames 202 b thereof may be arranged such that: each LED lead frame202 b has the first sidewalls 15 arranged along the length direction(Y-direction) of the lamp tube 1 with the second sidewalls 16 arrangedalong in the width direction (X-direction) of the lamp tube 1; each LEDlead frame 202 b has the first sidewalls 15 arranged along the widthdirection (X-direction) of the lamp tube 1 with the second sidewalls 16arranged along the length direction (Y-direction) of the lamp tube 1; orthe LED lead frames 202 b are arranged in a staggered manner. To reducegrainy effects caused by the LED light sources 202 when a user of theLED tube lamp observes the lamp tube thereof along the X-direction, itmay be enough to have the second sidewalls 16 of the LED lead frames 202b of the LED light sources 202 located in the outmost rows to blockuser's line of sight from seeing the LED light sources 202. Differentarrangements may be used for the second sidewalls 16 of the LED leadframes 202 b of one or several of the LED light sources 202 located inthe outmost two rows.

In summary, when a plurality of the LED light sources 202 are arrangedin a row extending along the length direction of the lamp tube 1, thesecond sidewalls 16 of the LED lead frames 202 b of all of the LED lightsources 202 located in the same row may be disposed in same straightlines to respectively form walls for blocking user's line of sightseeing the LED light sources 202. When a plurality of the LED lightsources 202 are arranged in a number of rows being located along thewidth direction of the lamp tube 1 and extending along the lengthdirection of the lamp tube 1, the second sidewalls 16 of the LED leadframes 202 b of all of the LED light sources 202 located in the outmosttwo rows may be disposed in straight lines to respectively form twowalls for blocking user's line of sight seeing the LED light sources202. The one or more than one rows located between the outmost rows mayhave the first sidewalls 15 and the second sidewalls 16 arranged in away the same as or different from that for the outmost rows.

As to FIG. 65, FIG. 65 illustrates a block diagram of an exemplary powersupply module in an LED tube lamp according to one embodiment of thepresent invention. This embodiment is a combination of some featuresdescribed in FIGS. 2, 52D, 51A, 50C, 52B, and 53A. According to thisembodiment, the LED tube lamp comprises a lamp tube 1, a heat shrinksleeve 190 covering on an outer surface of the lamp tube 1, an LED lightstrip 2 in the lamp tube 1, a plurality of LED light sources 202(similar to LEDs 631 in FIG. 53A) on the LED light strip 2, two end caps3 respectively coupled to two opposite ends of the lamp tube 1, and apower supply circuit 258 on the light strip 2. The power supply circuit258 comprises a plurality of electronic components.

The LED light strip 2 with the plurality of LED light sources 202 andpower supply circuit 258 is in the lamp tube 1. In other words, all theelectronic components of the power supply circuit 258 are on the lightstrip 2. Each of the end caps 3 comprises two conductive pins 301 forreceiving an external driving signal. The electrical connection betweenthe LED light strip 2 and the pins 301 may be achieved by wire bonding.

In one embodiment, the thickness of the heat shrink sleeve 190 is from20 um to 200 um and the heat shrink sleeve 190 is substantiallytransparent with respect to wavelength of light from the plurality ofLED light sources 202.

In one embodiment, the LED tube lamp further comprises a reflective film12 on an inner circumferential surface of the lamp tube 1. The ratio ofa circumferential length of the reflective film 12 along the innercircumferential surface of the lamp tube 1 to a circumferential lengthof the lamp tube 1 is about 0.3 to 0.5. The reflective film 12 has anopening 12 a for accommodating the LED light strip 2.

In one embodiment, the LED tube lamp further comprises a diffusion film13 on the inner surface of the lamp tube 1.

In one embodiment, the LED light strip 2 has a widened part occupying acircumference area of the inner surface of the lamp tube 1 and a ratioof the length of the LED light strip 2 along the circumferentialdirection to the circumferential length of the lamp tube 1 is about 0.3to 0.5.

In one embodiment, the LED light strip 2 is fixed by an adhesive sheetto an inner circumferential surface of the lamp tube.

In one embodiment, the power supply circuit 258 comprises a rectifyingcircuit 810, a filtering circuit 623, and an LED module 630. Therectifying circuit 810 is configured to receive and rectify the externaldriving signal from the two pins 301 (shown as pins 501 and 502 in FIG.65) of corresponding one of the end caps 3 and then produce a rectifiedsignal. In this embodiment, the power supply circuit 258 may comprisetwo rectifying circuits 810 (similar to the rectifying circuits 810 inFIG. 50C), which may respectively correspond to the rectifying circuit510 and the rectifying circuit 540 mentioned above in FIG. 49E.

The filtering circuit 623 is connected to the rectifying circuit 810 andconfigured to produce a filtered signal. In one embodiment, the powersupply circuit 258 may comprise two filtering circuits 623 and thefiltering circuits 623 may be referred to as filtering units 623 of FIG.52B. Each of the filtering circuits 623 filters the rectified signal asfrom corresponding one of the rectifying circuits 810 to produce afiltered signal. The LED module 630 has the plurality of LED lightsources 202 (631) for receiving the filtered signal and emitting light.

“Corresponding” in above paragraph means the electricalcircuit/component on the same side of the lamp tube 1. For example, therectifying circuit 810 on the left side of FIG. 65 corresponds to theend cap 3 on the left side, and the two pins 301 on the left side, thefiltering circuit 623 on the left side, if any. Likewise, the rectifyingcircuit 810 on the right side of FIG. 65 if any corresponds to the endcap 3 on the right side and the two pins 301 on the right side, and thefiltering circuit 623 on the right side, if any.

The power supply circuit 258 may further comprise a filtering unit 824as mentioned above in FIG. 52D. The filtering unit 824 is connectedbetween one pin of one of the two end caps and the rectifying circuit810. In some embodiments, the filtering unit 824 comprises an inductor828. The rectifying circuit 810 comprises a current-limiting capacitor642 and a rectifying unit 815 connected with the current-limitingcapacitor 642. The filtering circuit 623 comprises a capacitor 625. Inthis embodiment, the power supply circuit 258 may comprise fourfiltering units 824 as shown in FIG. 65 (the filtering unit 824 issimilar to that in FIG. 52D). The filtering units 824 are, respectively,connected between the four pins 301 and the corresponding rectifyingcircuits 810. Specifically, the pins 301 on the left side are connectedto the rectifying circuit 810 on the left side of the FIG. 65 while thepins 301 on the right side are connected to the rectifying circuit 810on the right side of the FIG. 65. In one embodiment, the filtering units824 each comprise an inductor 828. And each of the rectifying circuits810 comprises a current-limiting capacitor 642 and a half-waverectifying unit 815 connected with the current-limiting capacitor 642.It should be noted that current-limiting capacitor 642 can be a part of,or be regarded as belonging to, a terminal adapter circuit 541introduced in FIGS. 50C and 50D and also marked in FIG. 65. And each ofthe four inductors 828 in FIG. 65 can alternatively be regarded as apart of the terminal adapter circuit 541 in FIG. 65, since it'smentioned above that a terminal adapter circuit 541 (as in FIGS. 50C and50D) may comprise a resistor, a capacitor, an inductor, or anycombination thereof.

In one embodiment, each of the end caps 3 comprises a plurality ofopenings 304 formed one the end caps. The plurality of openings 304 ofone of the end caps 3 are symmetric to each other with respect to aplane passing through the middle of a line connecting the two pins 301and perpendicular to the line connecting the two pins 301. The number ofthe openings 304 on one of the end caps 3 is two. Alternatively, thenumber of the plurality of openings 304 on one of the end caps is threeand the three openings 304 are arranged in a shape of an arc. All theelectronic components of the power supply circuit 258 including therectifying circuits 810, the filtering circuits 623, the LED module 630,and the filtering units 824 are on the LED light strip 2. The filteringunits 824 are inductors 828 and the inductors 828 are closer to theopenings 304 of corresponding one of the end caps 3. Accordingly, heatfrom the inductors 828 may be dissipated more efficiently.

In one embodiment, the LED tube lamp further comprises a hot meltadhesive. The end caps 3 are adhered, respectively, to opposite ends ofthe lamp tube 1 via the hot melt adhesive.

The LED tube lamps according to various different embodiments of thepresent invention are described as above. With respect to an entire LEDtube lamp, the features including “having the structure-strengthened endregion”, “adopting the bendable circuit sheet as the LED light strip”,“coating the adhesive film on the inner surface of the lamp tube”,“coating the diffusion film on the inner surface of the lamp tube”,“covering the diffusion film in form of a sheet above the LED lightsources”, “coating the reflective film on the inner surface of the lamptube”, “the end cap including the thermal conductive member”, “the endcap including the magnetic metal member”, “the LED light source beingprovided with the lead frame”, and “utilizing the circuit board assemblyto connect the LED light strip and the power supply” may be applied inpractice singly or integrally such that only one of the features ispracticed or a number of the features are simultaneously practiced.

Furthermore, any of the features “having the structure-strengthened endregion”, “adopting the bendable circuit sheet as the LED light strip”,“coating the adhesive film on the inner surface of the lamp tube”,“coating the diffusion film on the inner surface of the lamp tube”,“covering the diffusion film in form of a sheet above the LED lightsources”, “coating the reflective film on the inner surface of the lamptube”, “the end cap including the thermal conductive member”, “the endcap including the magnetic metal member”, “the LED light source beingprovided with the lead frame”, “utilizing the circuit board assembly(including a long circuit sheet and a short circuit board) to connectthe LED light strip and the power supply”, “a rectifying circuit”, “afiltering circuit”, “a driving circuit”, “a terminal adapter circuit”,“an anti-flickering circuit”, “a protection circuit”, “a mode switchingcircuit”, “an overvoltage protection circuit”, “a ballast detectioncircuit”, “a ballast-compatible circuit”, “a filament-simulatingcircuit”, and “an auxiliary power module” includes any related technicalpoints and their variations and any combination thereof as described inthe abovementioned embodiments of the present invention.

As an example, the feature “having the structure-strengthened endregion” may include “the lamp tube includes a main body region, aplurality of rear end regions, and a transition region connecting themain body region and the rear end regions, wherein the two ends of thetransition region are arc-shaped in a cross-section view along the axialdirection of the lamp tube; the rear end regions are respectivelysleeved with end caps; the outer diameter of at least one of the rearend regions is less than the outer diameter of the main body region; theend caps have same outer diameters as that of the main body region.”

As an example, the feature “adopting the bendable circuit sheet as theLED light strip” includes “the connection between the bendable circuitsheet and the power supply is by way of wire bonding or solderingbonding; the bendable circuit sheet includes a wiring layer and adielectric layer arranged in a stacked manner; the bendable circuitsheet has a circuit protective layer made of ink to reflect lights andhas widened part along the circumferential direction of the lamp tube tofunction as a reflective film.”

As an example, the feature “coating the diffusion film on the innersurface of the lamp tube” may include “the composition of the diffusionfilm includes calcium carbonate, halogen calcium phosphate and aluminumoxide, or any combination thereof, and may further include thickener anda ceramic activated carbon; the diffusion film may be a sheet coveringthe LED light source.”

As an example, the feature “coating the reflective film on the innersurface of the lamp tube” may include “the LED light sources aredisposed above the reflective film, within an opening in the reflectivefilm or beside the reflective film.”

As an example, the feature “the end cap including the thermal conductivemember” may include “the end cap includes an electrically insulatingtube, the hot melt adhesive is partially or completely filled in theaccommodation space between the inner surface of the thermal conductivemember and the outer surface of the lamp tube.” The feature “the end capincluding the magnetic metal member” may include “the magnetic metalmember is circular or non-circular, has openings orindentation/embossment to reduce the contact area between the innerperipheral surface of the electrically insulating tube and the outersurface of the magnetic metal member; has supporting portions andprotruding portions to support the magnetic metal member or reduce thecontact area between the electrically insulating tube and the magneticmetal member.”

As an example, the feature “the LED light source being provided with thelead frame” may include “the lead frame has a recess for receive an LEDchip, the recess is enclosed by first sidewalls and second sidewallswith the first sidewalls being lower than the second sidewalls, whereinthe first sidewalls are arranged to locate along a length direction ofthe lamp tube while the second sidewalls are arranged to locate along awidth direction of the lamp tube.”

As an example, the feature “utilizing the circuit board assembly toconnect the LED light strip and the power supply” may include “thecircuit board assembly has a long circuit sheet and a short circuitboard that are adhered to each other with the short circuit board beingadjacent to the side edge of the long circuit sheet; the short circuitboard is provided with a power supply module to form the power supply;the short circuit board is stiffer than the long circuit sheet.”

According to the design of the power supply module, the external drivingsignal may be low frequency AC signal (e.g., commercial power), highfrequency AC signal (e.g., that provided by a ballast), or a DC signal(e.g., that provided by a battery), input into the LED tube lamp througha drive architecture of single-end power supply or dual-end powersupply. For the drive architecture of dual-end power supply, theexternal driving signal may be input by using only one end thereof assingle-end power supply.

The LED tube lamp may omit the rectifying circuit when the externaldriving signal is a DC signal.

According to the design of the rectifying circuit in the power supplymodule, there may be a signal rectifying circuit, or dual rectifyingcircuit. First and second rectifying circuits of the dual rectifyingcircuit are respectively coupled to the two end caps disposed on twoends of the LED tube lamp. The single rectifying circuit is applicableto the drive architecture of signal-end power supply, and the dualrectifying circuit is applicable to the drive architecture of dual-endpower supply. Furthermore, the LED tube lamp having at least onerectifying circuit is applicable to the drive architecture of lowfrequency AC signal, high frequency AC signal or DC signal.

The single rectifying circuit may be a half-wave rectifier circuit orfull-wave bridge rectifying circuit. The dual rectifying circuit maycomprise two half-wave rectifier circuits, two full-wave bridgerectifying circuits or one half-wave rectifier circuit and one full-wavebridge rectifying circuit.

According to the design of the pin in the power supply module, there maybe two pins in single end (the other end has no pin), two pins incorresponding end of two ends, or four pins in corresponding end of twoends. The designs of two pins in single end two pins in correspondingend of two ends are applicable to signal rectifying circuit design ofthe of the rectifying circuit. The design of four pins in correspondingend of two ends is applicable to dual rectifying circuit design of theof the rectifying circuit, and the external driving signal can bereceived by two pins in only one end or in two ends.

According to the design of the filtering circuit of the power supplymodule, there may be a single capacitor, or π filter circuit. Thefiltering circuit filers the high frequency component of the rectifiedsignal for providing a DC signal with a low ripple voltage as thefiltered signal. The filtering circuit also further comprises the LCfiltering circuit having a high impedance for a specific frequency forconforming to current limitations in specific frequencies of the ULstandard. Moreover, the filtering circuit according to some embodimentsfurther comprises a filtering unit coupled between a rectifying circuitand the pin(s) for reducing the EMI.

According to the design of the LED driving module of the power supplymodule according to some embodiments, the LED driving may comprise theLED module and the driving circuit or only the LED module. The LEDmodule may be connected with a voltage stabilization circuit for preventthe LED module from over voltage. The voltage stabilization circuit maybe a voltage clamping circuit, such as zener diode, DIAC and so on. Whenthe rectifying circuit has a capacitive circuit, in some embodiments,two capacitors are respectively coupled between corresponding two pinsin two end caps and so the two capacitors and the capacitive circuit asa voltage stabilization circuit perform a capacitive voltage divider.

If there are only the LED module in the LED driving module and theexternal driving signal is a high frequency AC signal, a capacitivecircuit is in at least one rectifying circuit and the capacitive circuitis connected in series with a half-wave rectifier circuit or a full-wavebridge rectifying circuit of the rectifying circuit and serves as acurrent modulation circuit to modulate the current of the LED module dueto that the capacitor equates a resistor for a high frequency signal.Thereby, even different ballasts provide high frequency signals withdifferent voltage levels, the current of the LED module can be modulatedinto a defined current range for preventing overcurrent. In addition, anenergy-releasing circuit is connected in parallel with the LED module.When the external driving signal is no longer supplied, theenergy-releasing circuit releases the energy stored in the filteringcircuit to lower a resonance effect of the filtering circuit and othercircuits for restraining the flicker of the LED module.

In some embodiments, if there are the LED module and the driving circuitin the LED driving module, the driving circuit may be a buck converter,a boost converter, or a buck-boost converter. The driving circuitstabilizes the current of the LED module at a defined current value, andthe defined current value may be modulated based on the external drivingsignal. For example, the defined current value may be increased with theincreasing of the level of the external driving signal and reduced withthe reducing of the level of the external driving signal. Moreover, amode switching circuit may be added between the LED module and thedriving circuit for switching the current from the filtering circuitdirectly or through the driving circuit inputting into the LED module.

A protection circuit may be additionally added to protect the LEDmodule. The protection circuit detects the current and/or the voltage ofthe LED module to determine whether to enable corresponding over currentand/or over voltage protection.

According to the design of the ballast detection circuit of the powersupply module, the ballast detection circuit is substantially connectedin parallel with a capacitor connected in series with the LED module anddetermines the external driving signal whether flowing through thecapacitor or the ballast detection circuit (i.e., bypassing thecapacitor) based on the frequency of the external driving signal. Thecapacitor may be a capacitive circuit in the rectifying circuit.

According to the design of the filament-simulating circuit of the powersupply module, there may be a single set of a parallel-connectedcapacitor and resistor, two serially connected sets, each having aparallel-connected capacitor and resistor, or a negative temperaturecoefficient circuit. The filament-simulating circuit is applicable toprogram-start ballast for avoiding the program-start ballast determiningthe filament abnormally, and so the compatibility of the LED tube lampwith program-start ballast is enhanced. Furthermore, thefilament-simulating circuit almost does not affect the compatibilitiesfor other ballasts, e.g., instant-start and rapid-start ballasts.

According to the design of the ballast-compatible circuit of the powersupply module in some embodiments, the ballast-compatible circuit can beconnected in series with the rectifying circuit or connected in parallelwith the filtering circuit and the LED driving module. Under the designof being connected in series with the rectifying circuit, theballast-compatible circuit is initially in a cutoff state and thenchanges to a conducting state in an objective delay. Under the design ofbeing connected in parallel with the filtering circuit and the LEDdriving module, the ballast-compatible circuit is initially in aconducting state and then changes to a cutoff state in an objectivedelay. The ballast-compatible circuit makes the electronic ballastreally activate during the starting stage and enhances the compatibilityfor instant-start ballast. Furthermore, the ballast-compatible circuitalmost does not affect the compatibilities with other ballasts, e.g.,program-start and rapid-start ballasts.

According to the design of the auxiliary power module of the powersupply module, the energy storage unit may be a battery or asupercapacitor, connected in parallel with the LED module. The auxiliarypower module is applicable to the LED driving module having the drivingcircuit.

According to the design of the LED module of the power supply module,the LED module comprises plural strings of LEDs connected in parallelwith each other, wherein each LED may have a single LED chip or pluralLED chips emitting different spectrums. Each LEDs in different LEDstrings may be connected with each other to form a mesh connection.

The above-mentioned features of the present invention can beaccomplished in any combination to improve the LED tube lamp, and theabove embodiments are described by way of example only. The presentinvention is not herein limited, and many variations are possiblewithout departing from the spirit of the present invention and the scopeas defined in the appended claims.

What is claimed is:
 1. An LED tube lamp, comprising: a lamp tube; a heatshrink sleeve covering on an outer surface of the lamp tube; an LEDlight strip in the lamp tube; a plurality of LED light sources on theLED light strip; two end caps respectively coupled to two opposite endsof the lamp tube, each of the end caps having two pins for receiving anexternal driving signal; and a power supply circuit comprising aplurality of electronic components, all of the electronic components ofthe power supply circuit being on the light strip, the plurality of theelectronic components of the power supply circuit comprising: fourfiltering units, two of the four filtering units being connected inseries between the two pins of one of the two end caps, and the othertwo of the four filtering units being connected in series between thetwo pins of the other of the two end caps; a first current-limitingcapacitor and a second current-limiting capacitor, one end of the firstcurrent-limiting capacitor connected to a connection node between thetwo filtering units connected in series, and one end of the secondcurrent-limiting capacitor connected to a connection node between theother two filtering units connected in series; two rectifying circuitscoupled to the LED light sources, one of the rectifying circuitsconnected to another end of the first current-limiting capacitor and theother rectifying circuit connected to another end of the secondcurrent-limiting capacitor; and a capacitor connected in parallel withthe LED light sources.
 2. The LED tube lamp according to claim 1,wherein a thickness of the heat shrink sleeve is from 20 um to 200 umand the heat shrink sleeve is substantially transparent with respect towavelength of light from the plurality of LED light sources.
 3. The LEDtube lamp according to claim 2, further comprising a reflective film onan inner circumferential surface of the lamp tube.
 4. The LED tube lampaccording to claim 3, wherein a ratio of a circumferential length of thereflective film along the inner circumferential surface of the lamp tubeto a circumferential length of the lamp tube is about 0.3 to 0.5.
 5. TheLED tube lamp according to claim 4, wherein the reflective film has anopening for accommodating the LED light strip.
 6. The LED tube lampaccording to claim 5, further comprising a diffusion film on the innersurface of the lamp tube.
 7. The LED tube lamp according to claim 2,wherein the LED light strip is fixed by an adhesive sheet to an innercircumferential surface of the lamp tube.
 8. The LED tube lamp accordingto claim 7, wherein the LED light strip has a widened part occupying acircumference area of the inner surface of the lamp tube and a ratio ofthe length of the LED light strip along the circumferential direction tothe circumferential length of the lamp tube is about 0.3 to 0.5.
 9. AnLED tube lamp, comprising: a lamp tube; an LED light strip in the lamptube; a plurality of LED light sources on the LED light strip; two endcaps respectively coupled to two opposite ends of the lamp tube, each ofthe end caps having two pins for receiving an external driving signal;and a power supply circuit having a plurality of electronic components,all of the electronic components of the power supply circuit being onthe light strip, the plurality of the electronic components of the powersupply circuit comprising: four filtering units, two of the fourfiltering units being connected in series between the two pins of one ofthe two end caps, and the other two of the four filtering units beingconnected in series between the two pins of the other of the two endcaps; a first current-limiting capacitor and a second current-limitingcapacitor, one end of the first current-limiting capacitor connected toa connection node between the two filtering units connected in series,and one end of the second current-limiting capacitor connected to aconnection node between the other two filtering units connected inseries; two rectifying circuits coupled to the LED light sources, one ofthe rectifying circuits connected to another end of the firstcurrent-limiting capacitor and the other rectifying circuit connected toanother end of the second current-limiting capacitor; and a capacitorconnected in parallel with the LED light sources; wherein each of theend caps comprises a plurality of openings formed thereon, and theplurality of openings of one of the end caps are symmetric to each otherwith respect to a plane passing through the middle of a line connectingthe two pins and perpendicular to the line connecting the two pins. 10.The LED tube lamp according to claim 9, further comprising a hot meltadhesive, wherein the end caps are adhered, respectively, to oppositeends of the lamp tube via the hot melt adhesive.
 11. The LED tube lampaccording to claim 9, wherein the number of the openings on one of theend caps is two.
 12. The LED tube lamp according to claim 9, wherein thenumber of the plurality of openings on one of the end caps is three, andthe three openings are arranged in a shape of an arc.
 13. The LED tubelamp according to claim 12, wherein the three openings are arranged in ashape of an arc with gradually varying lengths.
 14. The LED tube lampaccording to claim 9, wherein the LED light strip is fixed by anadhesive sheet to an inner circumferential surface of the lamp tube. 15.The LED tube lamp according to claim 14, wherein the LED light strip hasa widened part occupying a circumference area of the inner surface ofthe lamp tube and a ratio of the length of the LED light strip along thecircumferential direction to the circumferential length of the lamp tubeis about 0.3 to 0.5.
 16. An LED tube lamp, comprising: a lamp tube; aheat shrink sleeve covering on an outer surface of the lamp tube; an LEDlight strip in the lamp tube; a plurality of LED light sources on theLED light strip; two end caps respectively coupled to two opposite endsof the lamp tube, each of the end caps having two pins for receiving anexternal driving signal; and a power supply circuit on the light strip,the power supply circuit comprising: two rectifying circuits, one of therectifying circuits connected to the two pins of one of the two endcaps, the other rectifying circuit connected to the two pins of theother end cap, and each of the two rectifying circuits configured torectify the external driving signal to produce a rectified signal; afiltering circuit, connected to the two rectifying circuits andconfigured to produce a filtered signal; and an LED module having theplurality of LED light sources for emitting light; wherein the powersupply circuit further comprises four inductors, two of the fourinductors are connected in series between the two pins of one of the twoend caps, and the other two of the four inductors are connected inseries between the two pins of the other of the two end caps.
 17. TheLED tube lamp according to claim 16, wherein one of the two rectifyingcircuits comprises a current-limiting capacitor and a rectifying unitconnected with the current-limiting capacitor, and is connected to aconnection node between the two inductors connected in series betweenthe two pins of one of the two end caps; and the filtering circuitcomprises a capacitor.
 18. The LED tube lamp according to claim 17,wherein each of the end caps comprises a plurality of openings formedthereon, and the plurality of openings of one of the end caps aresymmetric to each other with respect to a plane passing through themiddle of a line connecting the two pins and perpendicular to the lineconnecting the two pins.
 19. The LED tube lamp according to claim 18,wherein the number of the openings on one of the end caps are two, thethickness of the heat shrink sleeve is from 20 um to 200 um and the heatshrink sleeve is substantially transparent with respect to wavelength oflight from the plurality of LED light sources.
 20. An LED tube lamp,comprising: a lamp tube; a heat shrink sleeve covering on an outersurface of the lamp tube; an LED light strip in the lamp tube; aplurality of LED light sources on the LED light strip; two end capsrespectively coupled to two opposite ends of the lamp tube, each of theend caps having two pins for receiving an external driving signal; and apower supply circuit on the light strip, the power supply circuitcomprising: two rectifying circuits, one of the rectifying circuitsconnected to the two pins of one of the two end caps, the otherrectifying circuit connected to the two pins of the other end cap, andeach of the two rectifying circuits configured to rectify the externaldriving signal to produce a rectified signal; a filtering circuit,connected to the two rectifying circuits and configured to produce afiltered signal; and an LED module having the plurality of LED lightsources for emitting light: wherein the power supply circuit furthercomprises an inductor connected between one pin of one of the two endcaps and one of the rectifying circuits, and the inductor is closer tothe openings of the one end cap which corresponds to the inductor thanthe other electronic components of the power supply circuit are.
 21. TheLED tube lamp according to claim 16, wherein the LED light strip isfixed by an adhesive sheet to an inner circumferential surface of thelamp tube.
 22. The LED tube lamp according to claim 21, wherein the LEDlight strip has a widened part occupying a circumference area of theinner surface of the lamp tube and a ratio of the length of the LEDlight strip along the circumferential direction to the circumferentiallength of the lamp tube is about 0.3 to 0.5.